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

But it's better when there's a lot, rather than a little;) Heroes 4 has variety, but Heroes 5 doesn't (IMHO);)
Example of variety:
Magic Theft - when a spell is cast, the target loses magic, which is transferred to the caster (demon effect)
Energy Theft - spells cost twice as much
Magic Shackles - the target takes damage when casting spells