Literally the worst part of Baldur's Gate is the combat system. It is objectively inferior when it comes to DnD implementation.
Yeah, I'm a big fan of BG, I played the second in particular something like ten times or so, from start to finish.
I still think the combat being real time was the most glaring flaw of the game, despise having some damn good encounter design to ALMOST make up for it.
Conversely, I liked a lot of the two Orginal Sin, but hwat I hated the most about them was their half-assed ruleset/progression system and the horrendous randomized itemization.
This automatically addresses both (at least to some extent) even just by merely being based on D&D.
No matter how I look at it, this is a win/win for me.
THAT SAID, I really think they should work on giving the UI and camera a more distinctive look and separate identity over the OS series.