Light cleric vs artillerist spell list. The extra 1d8 looks cute but potent cantrip or the dragon sorcerer's Cha to damage.
The extra d8 that looks cute and the artillerist gains at 5th level is +1d8 compared to the CHA bonus to damage at 8th level 3 levels worth of almost the exact same damage bonus.
We were comparing clerics and bards to artificers. This is another example of changing the class in comparison. The sorcerer is a completely different comparison that can pump out a lot of damage but suffers rapid resource loss in doing so and doesn't have the artificers versatility.
Draconic affinity comes at a closer level but without blowing sorcery points it's not better. It's actually slightly behind because a d8 can crit and the sorcerer will have +4 CHA bonus assuming no feats taken.
The light cleric adds:
burning hands -- cannons do this at will instead of using a spell slot
faerie fire -- this is on the artificer spell list before going to subclasses
flaming sphere -- this cost the bonus action you are already using for spiritual weapon or the concentraion for spirit guardians; it's on the alchemist list that you were knocking; cannons are a better use of the bonus action and don't cost concentration
scorching ray -- this is on the artillerist spell list
daylight -- this spell isn't available to the artillerist, but how is it making a difference here?
fireball -- this spell is on the artillerist spell list
Light domain spell list doesn't look like it's adding much at all, tbh, and the bonus damage is similar but later. The arcane firearm applies to other spells too, not just cantrips.
Additionally, the arcane firearm benefits from the enhanced arcane focus infusion.
Also the spell Spirit Guardiansin conjunction with a cantrip.
Great, but you are ignoring the cannon for either damage or healing that also work in conjunction with a cantrip. Concentration is still available to the artillerist to add faerie fire that you give up for spirit guardians to increase everyone's damage via advantage.
Spiritual Weapon as well.
This is the bonus action attack. Given that you were adding the 8th level bonus, these are 3d8 at 9th level. That's a closer level than the gap from arcane firearm to potent cantrip mentioned earlier. The range on this spell is not as good as the cannon bonus action damage. 1d8+3 when gained is less than 2d8 and the cleric needs to play catch up here.
Some clerics eg arcane and nature also get druid or wizard cantrips.
This doesn't help them with damage. Artificers have decent damage cantrips and have access to cantrips from cleric, druid, and wizard lists already.
Light cleric can upcast Spirit Guardians, use radiance of the dawn, a cantrip or whatever.
Artillerists can spend an action to blow up their cannon at higher levels too. It's a 20' radius 3d8 force damage attack will cost them a 1st level spell slot to replace and they still had the benefits up until that point on the first cannon plus the benefits of the second cannon replacing the first.
The cleric can upcast spiritual weapon too but the class only has so many slots to cast in the first place. That's replicating the only issue alchemists have -- burning through resources quickly.
1st level slots for cannons are far more efficient than upcasting, and the artillerist will still have higher spell slots to also use.
Tempest Cleric maximised shatters plus any of the other spells.
The arcane firearm benefits apply to shatter as well, or fireball. Better chance for targets to fail, a bit more damage on one of the rolls (not one of the targets ;-))
At 6th level assuming no feats when the tempest cleric can do that it's a 15 DC (base 8 + 3 prof + 4 WIS bonus) for 3d8 maximized and the artillerist is a 15 DC (base 8 + 3 prof +4 INT) for 4d8 damage. If we assume no bonus or penalty to CON save then the cleric's shatter will do 24 damage 70% of the time and 12 damage 30% of the time with 3 2nd-level slots and has 4 channel divinities to pull this off.
The artillerist will do 18 damage 70% of the time and 9 damage 30% of the time with 2 2nd-level slots. The artillerist has the same 3 2nd-level slots one level later at 7th level.
So a tempest cleric burning channel divinity would out-damage the artillerist and the artillerist would out-damage the tempest cleric in the same scenario when the cleric doesn't have channel divinity available or chooses not to use it for other reasons. What about other cleric subclasses? Do they suck because the tempest cleric has this option? The artillerist out-damages all of them with "that cute 1d8" so if the artificer sucks because of it they all must suck harder?
How is the cleric using shatters and spiritual weapon and spirit guardians and maintaining all this damage? The cleric only has so many spell slots and the artillerist is using cannons.
Etc... isn't an argument. Just sayin'. ;-)
Variant rule from Tasha's they all get the d8 at level 8.
Yes, but that replaces potent cantrip. It doesn't add to it. The only benefit is changing to that "cute 1d8" for players who would rather roll 1d8 once per turn regardless of cantrip or weapon attack instead of using divine strikes or potent cantrip with a fixed bonus.
So they dont nova that well and the artillerist and battlesmith extra sources of damage can get killed/destroyed.
Killing or destroying either is damage the party isn't taking. That's hp damage soak artillerists and battlesmiths are adding. It's a benefit, not a disadvantage.
The cleric can lose all of his damage in the same way, however. For example, level 3 to 10 each, cleric vs steel defender vs cannon vs homunculus...
Level | Cleric | Defender | Cannon | Homunculus | Artificer |
1 | 11 | n/a | n/a | n/a | 11 |
2 | 19 | n/a | n/a | 6 | 19 |
3 | 27 | 20 | 15 | 7 | 27 |
4 | 35 | 26 | 20 | 9 | 35 |
5 | 43 | 31 | 25 | 10 | 43 |
6 | 51 | 36 | 30 | 11 | 51 |
7 | 59 | 41 | 35 | 12 | 59 |
8 | 67 | 47 | 40 | 14 | 67 |
9 | 75 | 52 | 45 | 15 | 75 |
10 | 83 | 57 | 50 | 16 | 83 |
The defender is just short of the a 14 CON wizard in hp and the cannon has 18 AC not far behind. The difference is the defender and cannon can both be healed between every fight practically cost free using the mending cantrip but the cleric or artificer cannot.
The cleric can lose the bonus damage to a failed concentration check, counterspell, or dispel magic where the artificer cannot. The artillerist can replace the bonus damage with a 1st-level spell where the cleric cannot.
They don't nova as well as some other classes. That doesn't mean they don't nova, but what they do well is make efficient use of resources. Infusions don't use slots or concentration. Subclass abilities either don't use spell slots or use cheap 1st-level spell slots.
The artillerist doing 2d10+1d8 firebolts or whatever and adding 2d8 cannon damage with the free cannon before it might drop to damage and granting advantage through faerie fire is using a single 1st-level spell and accomplishing a lot with it. The light cleric doing 2d12 necrotic damage and adding 1d8+4 from spiritual weapon for a 2nd-level slot and 3d8 from spirit guardians for a 3rd-level slot.
2d8+1d8 is better than 2d12. 2d8 is better than 1d8+4. It's questionable on party make-up on how much damage faerie fire does but giving advantage to the group GMWs and SS's on top of the artificer's better accuracy from it is definitely meaningful.
I know the cleric adds a "cute 1d8" at 8th level but the artillerist adds another "cute 1d8" at 9th level, and another 3d8 from the second cannon at 15th level.
The at-will attacks for the artillerist later are 4d10+1d8 firebolts, +3d8 cannon1, +3d8 cannon2, before burning any slots or using concentration or any feat requirements or using any infusions yet. The cleric is 4d12+1d8 and then needs to burn slots to catch up. If the artificer wants to burn a slot for more damage then wall of fire or animate objects is available.
And level 5 is one of those cherry picked levels where it's a best case scenario for an artificer. The artillerist and battlesmith that's their best level relative to everything else.
Because they don't use those features for every level after that? ;-)
That's not at 5th-level. It's an ability that is used from 5th through 20th-levels gained at 5th level, which covers the majority of the levels you said you play at and consider.