D&D 5E Alchemist artificer house rule - impressions of balance

[humble minion]

So, I have a player in my game who is playing a dhampir alchemist artificer. His character concept is of a studious doctor (this is War of the Lance Dragonlance, so healing magic is largely unknown and doctors/healers are actually useful...) who was deliberately infected with dhampirism by unknown means and unknown parties at some time in the past. His alchemical abilities are the results of his investigation into the power and potential of his own vampiric blood. I have allowed him to make some spell list swaps etc to lean into this concept.

He's proposing a modification to the alchemist's Experimental Elixir. One of the possible outcomes of the dice roll for this feature (or one option you can choose, if you're spending a spell slot to activate the ability) is to create a potion of Alter Self with a duration of 10 minutes. The modification he's proposing is to replace this with a polymorph effect that turns the drinker into a bat or wolf.

I've already told him that the bat is a no-no until at least the level at which a druid can turn into a flying creature (we have a PC druid, I don't want to step on his toes). But what do people think about this house rule in general? Is it overpowered? 11 temp hp (from the wolf form) is a lot at low level, but the ability isn't going to scale well at higher level and as it's a polymorph rather than a wild shape, the drinker of the potion will regress to wolf mental ability scores. But on the other hand, once he has a few more spell slots under his belt (he's talking about multiclassing, possibly into wizard), he'd be able to have the whole party turn into bats at quite a low level. But on the other other hand, he could do something similar as-is with the Experimental Elixir ability that grants a flight speed.

Can anyone else think of any massively obvious pitfalls here?

(Also, can anyone recommend a decent DMsGuild product with a vampire class in it - a class that actually involves developing one's vampiric abilities? He's poking around the possibility of blood hunter, but it's not the most clean fit for what he's doing...)

 

[DEFCON 1]

I think the easiest way to keep things clean and "balanced" is just make sure the things he wants to accomplish (mechanically-- not worrying about the narrative flavor overlay) is at a power level equal to what a character could do with a matching game mechanic. In other words... find the character level another PC could do a similar thing and make those numbers align.

They want to turn into a wolf? Okay... just follow the mechanics of what a Druid PC can do with wildshape. When can they do it? What statblock do they use? What are the barriers for when and how quickly they turn and turn back? How does the wolf's power increase over further levels of the game? Basically... think about it as if you were to pluck the wildshape mechanic out of the Druid and plop it into the Artificer... what concessions would need to be made to not have this power overshadow the Druid while at the same time have enough mechanic heft to not just be like wearing a "wolf pelt" in human form? Keep the numbers on par and you probably are in good shape.

Likewise... wanting to turn all of the party into bats to let them fly? Well, at 5th level the Wizard class gets the Fly spell as a 3rd level slot and at higher levels / higher slots the Wizard can let more people Fly with that single casting (so two PCs with a 7th level caster / 4th level slot... three PCs with a 9th level caster / 5th level slot etc.). So if you give the Artificer a refluffed "Fly"-like ability in their spell list or as a class feature as part of the "vampirism"... you can follow those numbers to get an idea of what a typical party COULD be doing with group flying at specific levels assuming a normal case scenario of a Wizard PC in the party. Again... keep things aligned to what another party could do with a different class doing a similar thing and you'll have a better idea of just how "balanced" it would be.

 

[Tales and Chronicles]

This not overpowered, but it does replicate higher level features from other classes/archetypes (druids, transmuters). Furthermore, things like Cloak of the Bat is a 14th level artificer infusion.

You'd have to ask what exactly he wants from those abilities. If it's just for looks, I'd just refluff the Flight, Swiftness and Transformation potions into a bat-like or wolf-like shifting.

 

[Xeviat]

I wouldn't balk at some transformation magic being available as low as 1st level spells, so I don't think it would be a problem. 2nd level for winged flight then; fly at 3rd level still has advantages.

 

[Clint_L]

I think the fact that you have a druid in the party complicates the issue. Balance, like everything else, depends on context, and the druid player might have chosen that class specifically because they liked the concept of being the shapeshifter who could infiltrate, scout, etc. So now this other player is potentially stealing their thunder, on top of getting all the regular class features from artificer and dhampir.

 

[humble minion]

Yeah, I’m definitely planning on talking to the druid player first (he's playing a Stars druid who doesn’t often wild shape because Starry Form is great, but I’m going to ask if he’s ok with it anyway)