What would you change in Heroes of Might and Magic IV?

I don't understand: how can poison affect a Poisonous creature??? Why does an enemy demon steal mana and keep it for itself, when there is no mage on its side? But my demon can't do that??? What is the purpose of the Leprechaun??? Who is Gryphonhat, and why does the description of the True Blade say "only Gryphonhat can wield the True Blade"? There is no such hero in the editor!

That's all for now. I'll write more later.