Thank you all for the input.
Darryl, I changed Armageddon (Wish) as suggested: "earthquakes and meteors kill 20% of the population and of the units in most provinces of the world". And I added Lichcraft: "you don't need a second 'willing necromancer' to be transformed, the spell works like a summoning".
Peter, I changed FoA as suggested: "gives a 50% forge bonus and +1 level in each path for purposes of forging, including all those he does not have. (yes, an Astral-1 Sage can forge a Fever Fetish or a Rainbow Armor !)."
Yossar: I added Iron will in the list. It’s hard to understand why do some spells stack, and other do not. Same for items BTW (two Soul Contracts can give 2 Devils/t, but two Cauldrons of Broth are not cumulative). So I wrote the word “often” in my message
Cheers