What would you add to Heroes? (creative ideas only!)

I don't like the fact that Nagas are missing in Heroes 5. What makes them worse than the praised Rakshasa, or how they managed to squeeze Manticores into the Dungeon faction. And adding an Elemental Castle, purely as a neutral faction, without interfering with the plot and without upgrading creatures.

The thing is, Nagas are a separate faction in Ashan. They live on a peninsula between Irollan and the Silver Cities, and their capital is obviously the city of Karthal. They weren't included because they are sea creatures, and it would have been necessary to create a sea race, which would have taken a long time to balance. Also, they mostly maintained neutrality in the history of Ashan, but in Lords of the Realm, they wanted to make them as separate units: Naga, Crystal Dragon (they were in the editor in version 1.3), but then they abandoned this idea.