Well in Midkemia are different kinds of Magic and Magic Users:
1) The Divine Magic Users -Clerics: These are almost like teh Core Clerics. They heal, can turn Undead (Black Slayers in Silverthorn) and have some divining powers.
2) the arcane Spell Users
2.1) The human magicians of the lesser path. They have an elemental affinity and use a lot of items (srcolls, crystal globes etc.). They have deadly spells to, but no world-shaking powers.
2.2) The human magician of the greater path. They are like the core sorcerer with a wizards array of spells. Do not use Items (apart from the teleporting devices which are made by lesser path magicians). They have th world shaking powers.
3) others
3.1) hedge mages, witches seers etc.. these are all untrained humans, born with an affinity for an aspect of magic (ie. Rogen in Silverthorn for Divination - foresight). Most of them do not have significant powers. Nakor is unique, as he had connection to a good for a long time. He is neither cleric nor magician but a mixture of both with a sprinkling of monk. And he has large powers.
4) Elven magic.
The elven Spellweavers use a subtle magic that is tied to their environment (the elven forest). There they have great powers of offensive (sleeping glades) and defensive magic.
The Eldar do not take action in the books, but teach pug a lot of his knowledge. We can assume, that they have great powers.
5) Other non human magic
5.1) We can assume that the goblins have shamans that fill the role of magician and cleric. No flashy or world shaking powers. Adepts.
5.2.) The Cho-ja (sp?) Magicians in Mistress of the Emire have great defensive powers and can construct cities with their magic.
5.3) Valheru There are some Items (Thomas armor) that can be used but not active magic. So we just put this under artifacts.
5.4) Othereworldly magic: Demons of the fith circle, Lords of the Dread, The Hall of worlds, the oracle af Aal etc. I do not count them in.
(I do not have the books with me so there might be some more examples.)
So, the biggest issue to resolve is: How to make all different path of magic useable and equal in power ruleswise.
As I see it, a Spellweaver is a NPC class.
If you play in Midkemia, you do not have any Cho-ja.
If you sort out wild Talent (maybe use it as a background option for Humans), you only have to fix Clerics, Lesser Path and Greater Path Magicians.
That could be done if you give the LP Magicians the power to create items and some abilities to use them, it should balance out against the GP Magicians with their powers.
