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

I agree about the primal magic, but can we only replace spells?
Or can we add new ones? I'm not sure, but I think we can also add spells, because in Heroes 5.5, Orcs have more abilities and skills than other races (only for the Warrior class).
Remember, I once suggested an idea about summoning in each school of magic, based on copying spells.
We can do something similar here, taking ideas from parts 6 and 7 (in terms of spell ideas) and trying to incorporate them into primal magic.
We can immediately move the magic arrow spell there, and replace it in chaos magic with a fire spell (or an ice spell, or even both).
We can move the teleport spell from light magic to primal magic.
We can also try to create something like magical armor (defense and/or magic resistance increases, equal to the caster's knowledge).
We can create a phoenix summoning spell, like in the sixth part, take the texture from there, and apply it to paoka or someone else.
Another question: can we make it so that creatures temporarily gain certain abilities through spells? Like from runes? If so, we can create many more spells, based on the properties of runes.