You did warn us, but this is a big, rambling mess. I will do my best to respond to the parts of it that I can.
Let me start by saying this is a rant. It's a giant rat-king nest of run on sentences but the content is solid and worth considering when weighing in on the power level of Artificers if your group isn't going to casually look the other way to make the Artificer payable/fun. Having played an Artificer in a long term Eberron campaign in 5e through every iteration of the class since it was pitched as a wizard subclass, and having been asked to adapt my pcs mechanics through its various incarnations through the grueling slog of character progression as an artificer, I have a pretty in depth answer. Before I go into it I just want to give a disclaimer that the artificer class, in concept, has been my favorite character class since 3.5e and I have had fun playing one in 5e... Solely by the generous permission of the GM to allow it to make and innovate using the item creation system available to any class.
I love the concept of artificers, too! I always have! As a DM, I allowed my players to play the UA versions, as well as a few homebrew versions I came across that I liked (XP to Level 3's in a level 1-20 campaign, once).
In 5e the Artificer ends up falling short of its potential due to clunky oversights in game design that ultimately make for a class that, on paper, is capable of bringing a wide array of fun archetypes but in practice makes for the least cohesive class to play. For every inovative mechanic the class brings to the table to make its subclasses attractive, there seems to be an oversight in its implementation and those mechanics sieze up when forced to take into account the same core 5e mechanics that all other classes are bound to . The class ends up being the perpetual brides maid, never the bride when compared to other classes ( and I mean -all- other classes that are designed to fill that party niche). It is true that the scope of roles available to the artificer are impressive, but its range becomes meaningless when the reality sets in that the Artificer class too is locked to the far narrower strengths of the subclass you choose at 3rd level; any subclass of which is handily outclassed by all but the worst subclasses available to the core classes designed to fullfill its same niche.
I disagree (I wouldn't be responding unless I disagreed, but I wanted to make this clear). The Artificer, IMO, is one of the best designed classes in all of 5e, with well-thought-out abilities that permeate nearly every aspect of the class and its subclasses (not all, but nearly all. I'm looking at you, Alchemist), and it has a flexibility and versatility that was only seen in Warlocks in 5e up until Eberron: Rising from the Last War came out.
The most unexpected issue is that the artificer ends up being more multiple attribute dependent than anticipated, even for the subclasses that allow for substituting intelligence in their attack roles because that substitution is either limited to attacks made with magical weapons in the case of the Battlesmith or with armor specific weapons in the case of the Armorer. lets take a closer look at the mess that is Battlesmith under the microscope and you will see what I'm complaining about.
This is wrong. I'm sorry, but it's wrong. The Battlesmith, Artillerist, and Alchemist are no more MAD than the Hexblade Warlock. You need your Spellcasting Ability Score (INT or CHA) to be the highest of all of your Ability Scores, but you also need decent Dexterity (14 for Medium Armor, or 16 if you have/want Medium Armor Master) and good Constitution (16ish) in order to be as effective as you can be in combat.
That's not hard. With Point Buy/Standard Array and the new Tasha's Customize Your Origin feature, you can start out with
at least a 16 in both Constitution and Intelligence (or 15 CON and 17 INT if you want to set yourself up for half-feats in the future). Then, if you're using Standard Array, put your 13 in Dexterity and wait for a half-feat in the future (Resilient, Elven Accuracy if you're an elf/half-elf, Piercer/Slasher, Skill Expert, etc). That's 1 ASI to get yourself as MAD as you need to be, and then you'll have to use 2 more ASIs to max out your Spellcasting ability modifier at a +5 (like everyone else in the game has to). You get 5 ASIs (6 if you're a Vhuman or Custom Lineage character), so you still have 2-3 ASIs to put into whatever you want (Medium Armor Master, War Caster, Spell Sniper, etc). If you're a Half-Elf or Mountain Dwarf, you can use even less ASIs to complete your MADness.
As an Battlesmith Artificer your support role limited to the spells you know and using your pet's reaction wisely to impose disadvantage on enemy attacks. Compared to the other half casters you lose a fighting style in favor of an admittedly great set of cantrips, but will rarely if ever make use of them in combat due to the clunky requirement of weilding a set of tools or an infusion imbued item to cast those cantrips. Easy enough yeah? This means you have to have a dedicated hand to weilding either tools, or a nonmagical version of an item you have to soup up to end up on a net disadvantage (not -that "disadvantage"-) compared to the items other classes are getting for free as part of their loot from adventuring because your infusions (and primary weapon/item buffing spells) can only be used on non magical targets so if you plan on casting spells all the way through 20th level, you are still stuck holding tools, a mundane shield, or a mundane weapon.
You can use any infused item as a spellcasting focus for your Artificer spells. If you're a Battlesmith, you can use your Enhanced Weapon/Radiant Weapon/Repeating Shot/Repulsion Shield as your spellcasting focus.
Sure, you can't use any cool magic items that your DM gives you as a spellcasting focus, however, which IMO is a potential problem, but it's not that big of a deal, especially because quite a few of the infusions have unique effects that official magic items don't grant.
But the artificer has firearms proficiency and in theory the battlesmith is the subclass best equipped to make use of them right? Well you are going to take a hit to your ac because you wont be able to weild a shield because your nifty repeating shot infusion may create ammo for your gun but does nothing to get rid of the reload property guns have (which is different from the -loading- property crossbows have) so your second attack is as good as gone if you even pick up a firearm.
Repeating Shot still works on Firearms, because it ignores the Ammunition property. You don't need to reload any ammunition if the infusion makes it so your weapon doesn't need ammunition. You can have a Repeating Shot Pistol in one hand and a Shield (potentially a Repulsion Shield) in the other hand no problem. Sure, you can't do that for two-handed firearms, but every martial character that uses ranged weapons has to choose good ranged damage or better AC.
You still lag behind the guys with archery fighting style and their likely +1 ranged weapon, sharpshooter etc. Oh and to rub in more salt in the wound, you likely wont ever have the feats to get xbow expert, no less sharpshooter so have fun being at a constant disadvantage in melee.
You can still take Gunner or Crossbow Expert. You have enough ASIs for Crossbow Expert/Gunner and Sharpshooter.
Oh and here's another kicker ; your tailored bonus smite spells are all incompatible with ranged attacks so your special bonus spelllist is useless of you go that route.
Actually, all of the Smite Spells on the Battle Smith list work on all weapon attacks, including ranged ones. So, you can Branding Smite or Banishing Smite on your ranged weapon attacks.
More salt in your wound, you dont get to add your intelligence to your armor class in lieu of dexterity and are still bound to its strength requirements so you may as well do away with that major benefit since dexterity is now nearly as valuable as if you were attacking with it anyway.
No one except the Bladesinger during Bladesong gets to add their Intelligence to your Armor Class. Hexblades don't get to. Even armorers that choose to use Light or Medium Armor don't get to. This is an invalid complaint, just like complaining "my Paladin doesn't get to use Charisma for their attack and damage rolls!", IMO.
Your steel guardian is cool but any of the other artificers can make use of the almost equivalent iron guardian. While the artillerist can issue commands to both his turrets, if you decide to get an iron defender too, you wont ever get to do the same for multiple homonculi so thats a useless infusion.
Uh, no, they can't (not through the Artificer features, at least). The other Artificers don't get any feature that lets them get an Iron Defender. That's like complaining that a Beast-Master Ranger is useless because any DM can give any character an Animal Companion.
The arcane zap that your guardian can do is nice to provide some extra damage or healing but the damage is lackluster compared to the steady flow from features like hex, giantslayer, or Hunter's mark.
It's like a Paladin's Smite feature, but a bit less damage (or healing, if you want). Sure, it's no Hex, it doesn't take spell slots or action economy, can help allies that are at low hit points, isn't concentration, and can be stacked with Hex/Hunter's Mark if you get it through the Fey Touched Feat from Tasha's.
They took away your equivalent spell, arcane weapon even though it too could only be cast on a nonmagical weapon and thus was incompatible with your infusions, not because it was too powerful for you but because it could possibly be cherry picked and stacked by other classes and instead of giving you Hunter's mark or hex to fill that gap or making it a class feature that isn't easily dipped into they just left the void cementing the regret of not having played a ranger or hexblade crossbow warlock.
We don't know exactly why they got rid of Arcane Weapon. It is a shame, yes, but IMO, it's not a huge deal.
That and a human hireling with a healing Kit easily outclasses your healing abilities in 5e.
Uh, this is also not a valid complaint against artificers. This doesn't come up in most campaigns, and most DMs don't have NPCs like this.
Oh and don't bother with two handed weapons because of that earlier mentioned need to have a tool in hand or a mundane weapon infused up because there are no infusions like repeating shot or "fancy shield" to support two weapons and their feat support is still riddled with dexterity and or strength based dependencies and you don't have those due to the big benefit you enjoy of using your int, which also happens to remain the weakest stat in 5e.
Not for Artificers. INT is not the weakest stat in 5e for Artificers, it's the best stat. Artificers can also use Radiant Weapon on two-handed weapons, so you're wrong there, too. Also, you can use an infused weapon as a spellcasting focus, so you don't need a tool or other item in order to cast your spells. (And, no, Artificers are not dependent on Strength, especially because of the Armor of Magical Strength.
On the plus side you do get to be proficient in con saves so on the off chance you get to use one of the concentration support spells that the full casters got access to 7-10 levels ago and are able to upcast several times better might actually be a detriment compared to the cantrips you are giving up most of your subclass benefits every time you cast one.
Uh, there are plenty of good concentration spells that the Artificer gets at fairly early levels (Guidance, Create Bonfire, Tasha's Caustic Brew, Blur, Enlarge/Reduce, Invisibility, Levitate, Spider Climb, Web, etc). Also, you're not trading full casting for cantrips, because no one does that. You're trading Fighting Styles, a d10 hit die, martial weapons, and Extra Attack for Cantrips and Infusions, which is well-worth the trade, IMO.
Each of the Artificers subclasses have awful issues just like this whether it's its the artillerist being outclassed, outgunned, and out-supported by the (anything that can cast fireball 4 levels earlier),
Artillerists' Temporary Hit Points cannon does something that no one else in the game could do (up until the Twilight Cleric came out), grant a good amount of temporary hit points every round as a bonus action. They're not the best blasters (in terms of damage) in the game, but they were never meant to be.
the glaring issue of the Armorers weapons being about as effective as simple weapons unlike mundane simple weapons can be targetted by your infusions and spells, but at least you didnt have to worry about stength!
Uh, just about as good as simple weapons (in damage dice) that use elemental damage (and some of the best types of elemental damage), literally cannot be removed/disarmed from you unwillingly, using your Spellcasting modifier to hit instead of having to worry about Dexterity or Strength, and have benefits that none of the simple weapons in the game have (Thunder Gauntlets tank support, extra Lighting damage). So, yeah, they are better than simple weapons, and better than most martial weapons (if not in damage dice, they are in overall effects).
(Except when grappling, jumping, climbing or being feeble and unable to use magic weapons the DM hands out and your AC being outclassed most other defender types, if not other Artificers.
Who cares about Grappling, Jumping, Climbing, or Strength saving throws when you can get Armor of Magical Strength, Boots of Springing and Striding, a Rope of Climbing, Winged Boots, and similar magic items from your Infusions?
Also, you should have the best AC in the game. If you don't, your DM is either being overly-generous with magic items at the table, or you're in a party with people that max out AC and basically nothing else in their characters (through Paladins/martial-Clerics with Shield of Faith, Bladesingers with maxed out DEX and INT with the Shield spell, and similar characters). You'll have Enhanced Defense Armor (probably Plate), a Repulsion Shield (once you get to level 6), and a Cloak and Ring of Protection once you get high enough level to unlock those infusions through Replicate Magic Item (and you will have the attunement and infusion slots to have them, too, because of your Armor Modifications feature). That'll make your AC be at least 25 all the time (at level 14, though, but it will be high at previous levels, too). If you cast Haste on yourself, too, that will be a 27 for AC. You can also multiclass or take a feat to get Shield, so if you spam it enough, you'll have an effective AC of about 32. Good luck hitting that AC unless you're the Tarrasque.
Or the bonuses the alchemist gets to key spell types which feature prominently on their spelllist.?. Nope!
What the heck are you talking about? They get Ray of Sickness and Cloudkill, which do poison damage. They get Flaming Sphere to do Fire Damage, Acid Arrow to do Acid, and Blight to do necrotic damage. Those are all of the damage types that they get bonuses to through Alchemical Savant, and it takes up 5 of the 10 spells that they get from the Alchemist spell list. Then, they also get access to two healing spells through their subclass spell list and have other healing spells on their class spell list that can also benefit from the same feature.
They 100% have spells that can make use of the Alchemical Savant feature.
All this on top of the fact the Artificers big benefit, infusions, are essentially the equivalent of warlock infusions... er invocations except they eat up attunement slots and make you equip mundane items to gain their benefits,
They're not "essentially equivalent to Warlock invocations". They work similarly (through scaling, having a pool of them that you can choose from, and letting you change one that you know on a level up), but they're not equivalent. The benefits of Infusions are overall better than Warlock Invocations. There's a reason why Artificers get less Infused Items than Warlocks get Invocations Known, and that's because Infusions are more powerful and versatile (through infusions being allowed to be put on nearly any item, being able to swap out the infusions you know when you take a long rest, and being able to swap the items that are infused when you take a long rest).
Not all infusions take Attunement Slots (only 9 of the 15 do, and I'm not even counting Replicate Magic Item), and you can have other people attune to the magic items you create (including your Steel Defender/Homunculus Servant). You also want to attune to magic items if you get high enough level (due to the capstone ability). Then, there's absolutely no disadvantage to being "forced to equip mundane items", because IMO, I'd rather have the versatility of choosing what weapon/armor/shield that I want to be using every day instead of being tied down to an immutable DM-given magic item.
or the percent decrease to the cost of item creation despite no magic item having a price in 5e and the mechanics for making them left purposefully vaugue and unsupported as an optional system the DM has no obligation to include in their game. Imagine if the rogue and fighter instead of getting additional ability score improvements explicitly got feats and you are sol if the GM didn't want to include feats, but worse since at least then you get something. So many of the Artificers class features are item creation features DMs are incentivized to not include by the decision not to publish gold values for magic items.
There is a cost to making magic items, as described in the Downtime sections of the PHB/DMG and Xanathar's Guide of Everything (which does describe how to create magic items, even if it is vague, which is overall a good thing for the DMs), and the Artificers get more than enough features to cover for the Magic Item Savant features, even if they don't come up in play in the campaign (which most DMs should allow, but it won't make you suck if they don't allow it).
The biggest problem I see with the Artificer was making it's signature ability to use any magic item freely and use them as it's spellcasting niche to 14th level...
I have absolutely no idea what you're complaining about here.
A level which in a canon eberron game you have would count yourself among the rarest of individuals, the setting Elminsters and Mordenkainens, to have obtained so good luck ever making it there.
This is no valid criticism. Yes, you will be powerful. Yes, powerful characters are rare in 5e. However, that doesn't make the artificer suck anymore than it would suck to be a trillionaire because no one on Earth is a trillionaire yet. That's just a nonsensical complaint.
Tldr: if I had more time I would have written a shorter post.
I wish you had. Or, at least, have created different paragraphs.
