ONLY explained as errors? let's see.
1) Initial range of attributes are incorrect. Example: Dwarves can't start with 18 constitution.
levelling curve has been dramatically reduced, resulting in faster and more stat gains than the originals. Given you quickly end up at 18s everywhere even in the originals, it makes sense they would tweak starting stats down by a point here and there. Levelups lose a bit of shine when you're already at 18s by the midgame. I suspect the old stsrting stats will be restored in legacy mode when the old leveling curve is restored.
2) Party attack doesn't work. (There is a reason you can do this in the original game, even when no one is hostile!)
Almost certainly removed to close the numerous exploits related to it. In particular the unlimited healing in dungeons where HPs/SPs are designed to be a limited resource.
3) When night falls, the behavior of the mini-map changes with no explanation. Presumably it's using the dungeon behavior, although this makes little sense. (A night-time town still has street signs and etc)
If only there was some magical way to know which way you were facing so you could orient yourself to your map...