Юниты "Might & Magic Heroes VI"

Nagas? Don't they fit into Ashan? As far as I remember, in DM, you can find a sword made by Nagas.

One element shouldn't be stronger than another, so they can't be balanced.

And not only that, the developers wanted to introduce them in Heroes 5; I think they are the main candidate for a new race.
But then the tier-based hero formula doesn't work; let's assume
we put air, water, and fire in the core, and earth in the elite – we still need 3 more units (phoenixes are neutral, I won't mention magical elementals, and fairies are with the elves).