I'll pipe in and add some stuff too:
AI Pathing really does need more work, I'd like the characters to remain a bit tighter too in formation too, or have some kind of catch up system. I'm tired of accidental running into an encounter I couldn't see and having the characters who were just starting to catch up be halfway across the map behind my controlled character. It's incredibly annoying, because now I have reload, slowly frog hop so they stick with me, then trigger the encounter so I don't have to waste 5 turns just actually getting them into the battle. Original Sin's battle range sort of fixed this even though it was the source of massive amounts of abuse too, but I think just having the lagging characters finish sprinting up just behind the controlled one would be enough.
I generally agree with everything Jaisa said too, though yeah we can already jump over stuff.
Another note is that for people who don't know DnD, you should make it clear that some classes choose their subclass at another level, because it doesn't mention it in character creation, so you have some characters with really cool subtype options or extra features and then a class like ranger that's kind of like "Here's some flavor buffs, oh yeah, no pet, HAR HAR" and people get confused and worried. My friend was already freaking out about ranger being broken, and I told it it'll take time to choose his... which they're not really happy about, as DnD's level progress is REALLY slow., which is where the "online" terminology usually comes in on the tabletop.
Since tabletop is already very slow and people-driven, it's not so bad, but telling someone that they won't really "be" their class until around halfway or near to the cap can be hard, especially in a game as long as this. You guys noticed that and seem to be tweaking XP amounts, but this was always one of my biggest pet peeves with tabletop games turned computer games, and it's the literal translation between two very different platforms. It just doesn't work. A GM is infinitely more flexible and a good one will make sure their players are having fun an adapt, a game will just do what it was programmed to do and is very static.
Stuff like levels normally doesn't matter because encounters can feel like and there usually aren't THAT many major ones and several hour sessions don't quite span the same length a computer game might. You might have to bend the translation here too and stretch levels out or something, just a thought.