So I've mulled over some of the design elements in the document for a while, and while this is "white room" and not playtest, I just want to give some initial impressions.
1.) The Spell Damage Output (Nova) element of an Artificer isn't as bad as I thought.
I figured a class that has half the spell levels of a dedicated spellcaster would lag significantly behind other classes in nova-ing a BBEG when it came time. I was less wrong than I thought. Sure, an artillerist gets fireball at 9th level (when dedicated mages have had it since 5th) but the damage of fireball is such that isn't as far behind as I would assume. Its comperable to a cleric using flame strike (23 vs 22 for FS), lags slightly behind a sorc/wizard using cone of cold (23 vs 30 CC) or an infernal warlock using his own fireball (23 vs 29 due to 5th a lvl slot) but really looks bad vs a druid using blight (23 vs 33 for blight).
At 17th level, when every class has their final spell slots, the disparity is far greater; the artillerist artificer is going online with cone of cold (8 levels after the wizard got it) for 30 damage, which is surprisingly comparible to a cleric's harm (40), a druid's sunburst (35), or a bard max-cranking out shatter (37). Of course, a warlock can outpace it with finger of death (51) and all the classes combined don't match the broken glory of a sorcerer or wizard casting meteor swarm (116).
Final Conclusion: despite being a half-caster, artificers (esp artillerists) are comperable to a cleric, druid, or bard in terms of damage output, but lag behind the dedicated arcanists (warlock, sorc/wiz).
2.) Healing, on the Other Hand, with an artificer is terrible.
Third edition artificer's didn't heal. 4e ones did as they were leaders. 5e gives artificers (esp alchemists) the tools to heal, but do NOT rely on them as primary healers for long. Again using 9th level, an artificer restores 13 hp (+Int and if alchemist, double Int). That's equal to or slightly inferior to the ranger (13 + wis, which probably won't be as high as an artifer's Int), or a paladin using spell slots (but a paladin has lay on hands for a big 45 point heal if needed). Bards and Druids pull up next with 22 points per 5th level cure wounds (+ Wis/cha as appropriate) as do all non-life clerics (while life clerics heal 32 + Wis for a 5th level cure wounds). Additionally, bards, cleric,s and druids all got healing word (bonus-speed healing at range) and the mass healing spells (which allow multiple targets simultaneously). A paladin can also bust out Aura of Vitality for healing over time.
Beyond HP, artificers get a few status removal spells (lesser/greater restoration, revivify and even raise dead for alchemists) but again, they get these far later than a dedicated caster like a bard, cleric, or druid. The Alchemist can cheat cast lesser/greater restoration without spell slots at 6th and 14th levels, which is a tremendous boon but several levels after the other classes do. Still, its far better than the ranger (who only gets lesser restoration) and on par with a paladin (who gets lesser and greater on the same table, along with revivify and can use their lay on hands as a lesser restoration as well).
Final Conclusion: Don't rely on an alchemist artificer as your sole healer, but they are serviceable backups like other half-casters are.
3.) Arcane Armament is a Trap.
At 5th level, an artificer gets 2 attacks with the odd caveat they must be with a magical weapon. Assuming they meet this requirement, that puts them on par with most "martial" classes for 2nd attack (bbn, ftr, pld, rgr, mnk) as well as bladelocks (thirsting blade) and ahead of valor bards. However, the reason I call this a trap is threefold.
a.) the requirement for a magical weapon means that, barring a generous DM or extenuating circumstances, you're going to need to burn an infusion on Enhanced Weapon to use it. That means you really have 1 less infused item per day if you plan to attack twice.
b.) The artificer only has simple weapons and crossbows (we're ignoring firearms, they're optional), the latter cannot be used to attack twice unless you sink a feat into crossbow mastery. So assuming you didn't use your ASI on it (or weren't a human), the best weapons you have are either d6's or d8's two handed. (Again, we're ignoring racial weapons, but elf and dwarf artificers do look more tempting due to this). All other two-attack classes have some access to martial melee weapons (either due to class or subclasas, or bladelocks being proficient in their blades) or scale better (monks, but they get more attacks to make up for it).
c.) Your Strength or Dex Score aren't going to be a good as a dedicated warriors. A dedicated attack class will have a 16 or 18 by 5th level, and while you have a +1 to hit/damage thank to it being magical, at best you're probably only sinking a 14 in either score due to INT being your primary king stat. Additionally, you're probably not increasing said stats in favor of your caster stat, while a barbarian is upping his Str or a Monk his Dex, and your magical edge is lost the minute THEY find a magical weapon of their own. Lastly, you lack any sort of damage booster beyond arcane weapon (the artificer version of hex/hunter's mark). Fighter's get Fighting Styles, Barbarian's get rage, paladin's get smite, rangers get bonuses for being a hunter, and valor bards can even use Inspiration.
This makes Arcane Armament very build-specific and situational. Its fair to say you are not replacing a fighter, barbarbian, ranger, or paladin in combat, and you might, at best, make squint substitute for a valor bard or bladelock IF you manage to find a way to get access to a martial weapon or don't mind spears or quarterstaves. If you insist on going ranged, either bite the bullet and invest in crossbow mastery OR invest in a shortbow instead. OR don't bother; firebolt cast from an artillerists wand or using alchemy to cast poison spray or acid splash is a far superior damage output.
Final Conclusion: Unless you are building around AA, just use cantrips. This feature belongs in a subclass dedicated to weapon/armor enhancing, not the main class.
4.) For a Cantrip-Focused class, Artificer's don't get enough Cantrips.
Jeremy Crawford said he viewed the artificer as being a class than has versatility as its main feature. Its obvious that they wanted the artificer to be versatile with their cantrips, both from their retraining (the only class that lets you retain cantrips) and their 10th level ability (which reduces to the wait from once per level to once per rest). Additionally, the artificer has a long-list of cantrips, many fitting the flavor of the magical tinkerer ability.
Its just, they learn new ones at such a slow rate, you're mostly locked into your choices regardless.
To start: While starting with 2 is fine (on par with the bard, druid, and warlock), they don't get a 3rd until 10th level. Every other class has learned two in that amount of time. An artillertist gets a free one at 6th level (via his prototype wand) but beyond that, you get two. Sure, you can swap them out once per level, but that assumes a.) you know what the next level is going bring so you can swap out ray of frost for firebolt or message. b.) You don't have a cantrip that it important to your subclass (such as acid splash, poison spray for alchemists or mending for artillerists). So most artificers will have one attack cantrip and maybe one utility cantrip (like mending, light or such) for nearly half your adventuring carreer, only swapping them when you know something's going to change or you get bored with one you have.
In my opinion, an artificer should get the normal progression of 2 cantrip full caster (start at 2, go to 3 at fourth and max out at 4 at tenth). Additionally, I think they should move "The Right Cantrip for the Job" down (to say, 5th level and bump arcane armament?) allowing them crazy versatility with their cantrips. This would put them on part with a warlock, trading the higher level arcanas for wider versatility in cantrips. Because right now, the artificer doesn't feel very versatile in his cantrips, he feels more like a two-trick pony.
Final Conclusion: Give the artificer more cantrips!
