My 2 cents on your question is that the game must do quite well but it'll do a lot better in the near future when gamers will start to hear more and more positive things about Divinity II.
This games deserves to do well in our nowadays unpolished and boring game market.
Like many peeps out there already said, including me, this game is a pure jewel. But sadly too many gamers go out on those so-called NA pro reviewers websites and read bad things about it (and those same reviewers give Oblivion a 9.3/10 and 6.5/10 for Divinity II!?!??). Sure it's all a matter of opinions but this game deserves to be with the best since it's one of the best RPGs out there.
I'm a little frustrated about this. Every game store here will have literally tons of copies of "big name games" (games from well known developpers) and when you ask them about a game like Divinity II they don't know what the $hit it is...and they have the insolence to call themselves video game stores...
Sorry i'm a little pissed...
But yeah, I think this game is doing very well and most importantly, it's players knows something about quality.
Cheers to Larian and everyone!