To be honest it's so different in so many aspects( 20 years of technology advancement aside -> Ressource management was at least tackled in BG2 for instance even if barely) I don't think there is even any point of saying if it's better or worse.
TLDR: @OP you mentioned you were never fond of Bioware games well.... the bioware game in all of BG3 is still to be found, it's really a Larian game in all possible aspects with D&d on top of it and BG2 in all of this is really an inspiration at best.
At least mechanics wise. Story wise I think here and there Bhaal and the story from BG2 will play a role.
I have to agree too that the writing style in BG2 wasn't necessarily perfect but Bioware back then in that departement did quite good in my opinion while Larian in some situations tends to use companion characters as a tool for exposition scenes way too often. Mostly dialogues with companions while way less present in the game felt a bit more organic as far as i'm concerned. BG3 did get way better in that regard between the 1st EA release and my last playthrough on patch #8 so I remain hopefull.
Worth noting I experienced BG2 for the first time....in polish. And polish voice acting for BG2 is simply a master piece. All actors were on complete crack, they did an insane job. And it helped a lot to create an unforgetable experience for the time. I'm replaying BG2 now with mods in english and I have to say BG3 voice actors are way better than what Bioware did in the english version back then.
In the end BG2 was simply gigantic( physically, like it was more than 100 hours of gameplay) for it's time. BG3 is aiming to be at least that long if not more( they mentioned it's going to be 3 times larger than DOS2 which would point at 150 hours of gameplay if you go relatively slow and don't just pass all dialogues and rush the main quest).
I don't think it's fair for two products separated by 20 years to call one better than the other one.
BG2 , nostalgia aside, earned it's place mostly by being either insanely large content-wise or pretending it's large in some areas( like for instance the size of the map.BG2 really isn't that big at all).
If anything, BG3 is going to be just as big and it has to do something that other games never did before and while for instance swarm AI is a very good example of an improvement we are missing D/N cycle which to some( like me ) feels like a huge drawback even if it's just a detail in the end.
