Oh... I should've noted a bit more about the Sanguine Heritage spell:
The reason you can access it is because I modded it--I changed it over to nation 4 which changes it from a theme spell to a standard national spell (very useful--I wasn't sure if it'd work, but it did).
In order to cast it you need 3 Astral and 3 Death--Fravartin can be enhanced to cast this spell, but none of the recruitable wizards can cast it without Empowerment.
The Sha'ir has an Elemental random and a Research penalty of -3. He is not a good researcher (he gets 1pt/50 or 1pt/12.5 at Magic Scale-3). I can see how he would be advantageous at Magic-3... I intended for Persia to have slow research. If it works (I haven't checked yet), I might give him a research penalty like -6 to block his research at all Magic scales.
I also thought the Immortals might be a bit cheap

They're quite effective.