I wouldn't mind having a level 6 hero myself, but not from the Might and Magic series (since there's nothing special about them), but rather a Priest/Inquisitor/Confessor from Heroes of Might and Magic.

Do you really want to buy these models?:)

People don't really have any special problems with this - except maybe with the angel heroes, and I also didn't like the idea of changing the color of Duncan's and Duncan-like heroes' quiver, a flag is also needed.
The problem arises when we create a "screaming" hero. Making "screaming" heroes is a faux pas, but in the case where this hero has a different racial affiliation, it is necessary because the standard model simply doesn't fit (that is, the problem will arise with angel heroes, djinn heroes, ifrit heroes, minotaur heroes, etc.)