When I first heard that this game even existed I was really surprised and then relieved that it would be done by Larian instead of Bioware... given their state now I couldn't trust them with a sequel such as this. However I've played Divinity Original Sin and will play the sequel when I get around to it, and Original Sin is one of my favourite fantasy RPGs I've ever played, so I'm confident Larian will do well here.
I do have some general suggestions - Baldur's Gate and Divinity have contrasting tones in a sense. I don't want to see a Baldur's gate that gets too wacky and silly for its own good; hopefully the developers know exactly the balanced kind of dark but sometimes silly setting in D&D.
I do hope with the companions that they focus on quality over quantity and make all of them as interesting as possible with their side quest arcs similar to BG2. I feel like there is an opportunity here for dragons too... I preface this by saying that in the D&D universe, with both books and games, that the dichotomy of metallic and chromatic dragons being "good' and "evil" doesn't feel very fleshed out or explained wherever they appear. I'd really like to see some story arc with dragons or mages/researchers exploring this. Having a "good" dragon that actually is evil or a an "evil" dragon actually being smart and not being a murderous monster would make for an interesting story/lore avenue for this game to explore. Even better is if one such abnormal dragon could be a party member... after all pretty much all dragons can take human forms, and the closest we ever got to a dragon party member in a game is Deekin from Neverwinter Nights.