Disjointed and bad story, bad mechanics, flat characters outside of romance to name a few things.
I think that if we had a chat about what we dislike about BG3 we would find a lot of common, but I am afraid those work as intended. There is a lot of feedback that's been given throughout Early Access, that it seems Larian wasn't interested in taking on board - I doubt the release has changed it, especially with the universal praise.