The Artificer has, as I see it, three basic problems.
- No ability to make permanent magic items (something that massively incentivises consumables) or cost discounts (Magic Mouths, Continual Flames, and Glyphs of Warding should all be very low cost spells if not free for Artificers).
- A power curve that (in part due to attunement rules) is very dependent on how generous the DM is in terms of loot
- Almost no synergies (unlike the paladin and ranger and like the D&Done warlock) to the point it frequently works badly with magic weapons
- Bad benchmarking (which isn't a separate problem from the previous two) that compares unfavourably to the PHB Ranger
This is entirely independent from Alchemist needing a huge tune-up. Every class has at least one subclass that needs a tune-up, and the other three subclasses are better
The permanent items problem feels as if it's missing from the class concept. And the power curve - you have a three attunement limit. Yes, OK, the Artificer can get five. But the core issue here is that an Artificer in a group where there are no other magic weapons is a different prospect from one with a Monty Haul DM. These are two issues where the concept isn't met. But even if we assume it was (there should definitely
be infusions for sharpening existing magic weapons for example, as well as a "everyone in the party has a +1 weapon until the next long rest infusion" and a permanent every few levels) this wouldn't fix the round to round play experience.
The core reason that the Paladin and Ranger work
in combat is that in most rounds what they do is greater than the individual best of their abilities. The obvious case is that if the Paladin just hit people or
cast spells they would basically be an inferior fighter or cleric in that round - but they hit people and
smite at the same time increasing their damage output because they can grab power from two pools at once. (And the best controlled condition for enemies is dead). Rangers aren't just good archers; they are good archers who stack that with Hunter's Mark and have extra damage per round in their subclass - and they aren't just good at stealth, they stack that with the frankly broken Pass Without Trace to become amazing at stealth. The lifeblood of hybrids is the ability to draw from both their power sources to reach peaks their partial access to either wouldn't give.
The Artificer? No free actions. Their only bonus action L1 spells are Expeditious Retreat and Sanctuary, L2 it's Kinetic Jaunt and Magic Weapon (that overlaps their infusions of course), and L3 it's just Ashardlon's Stride. And the only reaction spells on the entire
Artificer list are Absorb Elements and Featherfall. Literally the only way of using spell slots Artificers have that don't make them inferior wizards or clerics for while casting are light movement spells (no Misty Step) and Absorb Elements. (Or, I suppose, standard wizards/clerics if casting a cantrip). And their weapon damage output unless they have a useful subclass is best described as "wet pool noodle"; they just get a single attack and have to use a secondary stat.
Which brings us on to the lack of synergies in their subclasses.
Ignoring the obviously undertuned Alchemist we'll start with the armourer. They get second attack? Great! It takes them out of wet pool noodle territory but not into specialist combatant territory. The armour's special weapon is a trap, especially because you can't enchant it or infuse it before level 9 without giving up magic armour or armour infusions.
Let's take a simple comparison of a badly built jack of all trades ranger who's gone dex primary to match your Int, has (for some strange reason) gone Defensive style, and refuses to use Hunter's Mark.
- In Guardian Mode you match the Ranger's damage output in melee (1d8 + Int vs 1d8+ Dex) assuming they don't remember to proc their subclass bonus damage. You match their AC. Your only real advantage is your Defensive Field for temp hit points equal to your level proficiency times per day. (This, incidently, is the same sort of damage level as one of the bard melee subclasses).
- In Infiltrator mode you do d6 ranged damage (vs a bow's d8), and have an extra d6 damage as a proc (vs most subclasses d8). You have a movement buff, and you have a stealth buff to make up for their being Dex-primary.
Yeah, this isn't looking too good. You're basically comparable in combat to a PHB only Ranger who has gone defensive style and who can change from ranged to melee within a round rather than having to first take off their armour then put on a new set. You've spells but so do they. And you've utility from Infusions - but they have some. And they are better at using magic weapons than you. Whoever worked out the Armourer's benchmark did a terrible job. If the PHB ranger uses Hunter's Mark and archery style it's all over.
The artillerist almost
works. The spell list at least gives you Shield, so that's nice (and gives you a spell you can use in combat). A fundamental problem with the Artillerist is that the Cannon (a) has 1 hour duration and (b) takes limited resources to replace. If the PCs are always on the offensive this isn't a problem - but if the party ever needs long term vigilance (e.g. keeping watch), gets ambushed, or has a long term even the artificer can either be basically an alchemist in combat or can waste their first turn and a spell resummoning the Eldritch Cannon. (The Protector canon not scaling is another issue; average 8.5 temp hit points for multiple people is great at level 4 - and 9.5 is almost pointless at level 20). Also again benchmarking against the PHB Ranger other than at levels 3-4 just isn't good; with Firebolt and a Force Ballista you're comparable to an archery ranger who's not using Hunter's Mark and who doesn't have good magic bow.
The Battle Smith is far the best of the set. First they get Shield
meaning they get to attack and cast something useful. Second they are literally the only Artificer subclass that gets to make full use of the artificer's ability to make themselves magic weapons as they get both Extra Attack and Int on attack and damage rolls with a magic (including infused) weapon. This also means that their baseline combat output without
the Steel Defender is roughly on a par with the Armourer - and unlike the Artillerist the Steel Defender sticks around. With the Steel Defender? They get to use their bonus action to make a third attack. We're in two weapon fighting style territory here - but with the artificer able to hang back and use the Steel Defender to soak up damage and either use a bow or a polearm. You actually have synergies within the class here. And because of it this is the only artificer subclass that can even hang with the PHB Ranger.