there's a limit everywhere, like a saturation point
the only option is to either move in a different direction, like in the fourth installment, or just add more features to the third – graphics, 3D, etc.
there's no need to invent anything; everything has already been invented. If you want to invent something, make a new game. If you want to make another Heroes game, make an upgrade to the third one, and everything else is a must-have!!!!
Added after 12 minutes
magic defense is already good
it was annoying that the arrow attacks equally against heroes of level five and level twenty-five
it would be logical if they don't change their minds
mages greatly increase their magic defense, while warriors increase it almost not at all
if you're a warrior, fight with warriors, and a mage needs to use magic.