My worries regarding the final game are identical to my current gripes with the EA, after patch 4 and the panel it seems that what we see now in EA is more or less what we'll get - plus content and minus (some) bugs, hopefully. I've read somewhere that they changed DOS2 (or was it 1?) rather dramatically during the EA, but that is clearly not happening with BG3.

So:
1. Combat system
2. Abundance of dice rolls (RNG) outside combat + uncreative/boring failures. I mean they change/ignore many parts of the ruleset that might've actually helped the game and at the same time make sure THIS is implemented in the most obnoxious way possible for a cRPG with quicksave+quickload functionality? Why? The designers of the original two games really knew what to keep and what to toss compared to this, IMHO.
3.-6. in no particular order (kinda related): Camera controls, character+party controls, interface, inventory management
7. Larianization and/or ignorance of everything D&D and Forgotten Realms, including stuff established in BG1/2 (not that D&D or FR as wholes are very consistent)
8. Dating sim. Though a well-written & well-scripted romance is welcome, so far it seems that Larian is going with the "quantity, fan service & attainability > quality" approach. I guess I'm getting too old and a sex scene is not large enough a motivation for approval-hoarding, heh...