Apart from what's already been mentioned, the whole camp and quick rest system. The former's so convient it's jarring, and the latter i just don't like too much.
I'd like it all much better if the camp was a fixed location on the map, like in DA:O, while rest on the field worked like in Pathfinder:Kingmaker.
You do realize that in DA:O you could quick travel to camp just the same is this game right? The only difference is you could have a random encounter porting to camp.
Nah, you couldn't. You had to access the map by reaching the area's edge/traveling point, and then you could go to camp. Couldn't teleport to it from the middle of a city, or from the deeproads.
In BG3 you press M from the Underdark and bam, you're there.