The castle of your dreams.

I would leave everything as is and add a castle built from the available neutral creatures (level 1 - hobbits, level 2 - thieves, level 3 - nomads, level 4 - snipers, level 5 - trolls, level 6 - wizards, level 7 - I don't know, either mountain drakes from WoG or magical dragonlings, or some new type of dragon, because it's easy to come up with new dragons in Heroes - the first adjective that comes to mind + dragon = a new type of dragon)), I would add the castle of the Regnan Empire (during the period when it had not yet fallen apart, and not during the period of Might and Magic 8, of course, primarily it would be a pirate castle with bonuses at sea), and, just for fun