RTF is a global modification that replaces all towns in the game.

and in my opinion, it works well for humans; it suits them. It just needs to be reworked so that it acts as support for the Orcs, meaning you place it on any of your units, and when they attack, the hero attacks as well.

1. The last two levels are occupied by Luminaries and unicorns, which means you can't change the units, and on the 4th level, it's all women (the first 3 levels were men, and then the gender changed 0_o). 2. That's what a mod is for; not everything will be the same as in the "pure" Heroes 5 :)

Added 1 minute ago

but what is there to implement? There's only 1 slot for a level 7 unit, and if you build dragons or angels, there will be no room to build anything else, or does the concept itself not allow adding two such buildings?

I don't understand this myself, so I'm saying: if it could be implemented, then this would be the way to do it; someone would have suggested it by now.