Maybe someone has already written about this. Oh well.
First, about what I wouldn't want to remove:
1. The skill system; I liked it the most.
2. The ability for the hero to move separately.
3. The map editor and quest objects on the map – you can create such wonders there!!! In comparison, it looks primitive in Heroes of Might and Magic III.
I can't think of anything else.

Now, what I would like to change (remove):
1. Some castles (for example, why did they combine Necropolis with Inferno?).
2. Some creatures (old ones could be added, new ones could be left + in my opinion, the graphics of the creatures are worse than in the third game).
3. This is just my opinion, but the heroes' walking animation should be changed.