I'm so excited! I didn't expect extended ending content for at least 6 more months! I've been trying to be as patient as I can but the endings are really my biggest gripe with the game.
I'm hoping that since this is coming out a lot sooner than I thought that it isn't going to be half-baked and that there's really some substantial closure (and please please tell me that they're going to fix Astarion's ending please).
I'm also hoping they plug the bugs that are plaguing people in Act 3. I've never experienced them but I empathize with people who haven't been able to progress due to them. Though, I do believe some people exaggerate when using the term "unplayable", but again, if these bugs are legitimately causing the game to break in an unplayable way, I hope they've fixed that completely.
I don't know if there are any bugs crashing the game (not sure about the Act 3 lag - haven't experienced it in the first area of Act 3), but there are several that brick or in other ways ruin main/character quests, and that is certainly no way to experience the game's story. Maybe if you are affected by these you can play to the end, but it is not how anyone would want to play BG3 (and even endings are not working properly from what I hear). People who replay the game might be less affected by this, but even when replaying BG3 there is lots of completely new material that no one wants ruined.