For full classes, this game will feel incomplete to me without Artificer being an option. "But it's not set in Eberron." So? That doesn't matter. Just because there's not already a place full of people doing what artificer's do as a commonplace thing doesn't mean there can't be some people out there trying to do such things. The only distinction would be that it doesn't look as advanced as you'd expect of an Eberron setting. Heck, you could even justify random enemy goblin artificer's where there creations would be jurry-rigged out of scrap. The very class page for Artificers already states they're found throughought the entire DnD multiverse, not just the Eberron setting, which can easily include this game. Honestly I don't rightly get where's there's so many people out there who think Artificer = Eberron only, thus causing me to add these extra sentences. But maybe the people causing that aren't in the BG community anyway, idk.
Regarding subclasses, especially considering all the Illythid involvement, I would *really* want all the more "lovecraftian" subclasses. Aberrant mind being the first to come to mind, pun half intended.
Artificer is not eberron specific anymore, and even then wasn't really. Artificer is a full class that is meant to be adaptable to any setting with some flavor work.
This is pretty true, Artificer was introduced in 3.5 eberron campaign setting. Along with Changeling, warforged, and whatever tattoos feats...i think they were called dragon marks, something like that. Artificer main stick was enchanting armor/weapons and crafting, including crafting homunculus pets. I can imagine it would go well with pretty much any setting with magic included in it.
Edit* that is 3.5 though, I can't imagine it changed much for 5e, could be wrong.
Same thing happened in 4e and 5e, but 5e also moved it into Tasha's to make it even more clear that Artificer is not exclusive to Eberron. And they also made it clear that flavor can be anything, an artillerist can use wands or guns, an alchemis magical or scientific brews, and a battlesmith can retheme their steel defender to be a rocky or iron golem that is more magical than mechanical.