What other buildings do you think could be added to the castles? (Because in Heroes 5, almost no new buildings were added; they mostly copied them from Heroes 3).
Also, I don't like that some buildings in Heroes 5 are unreasonably expensive. For example, why does a Fortress cost 5000 when it doesn't increase the army size and only adds a wall? A Citadel costs the same, but it adds both an army and a moat with a tower. Or the upgrades for certain creatures; for example, upgrading a Priest costs 8000, but no creature of level 5 costs that much, and in general, upgrades in Heroes 3 were much cheaper. The only positive thing is that upgrading level 7 creatures has become cheaper compared to Heroes 3.