The discussion in this thread has touched on what I see as a problem in the current rule system. If I wanted to set a campaign in the West of Glorantha, including Loskalm, Seshnela, or Ralios, I feel like I should be able to make a character who only uses sorcery as their main form of magic. I feel like the Guide implies that this is how many Westerners practice magic, including zzaburi wizards, Loskalmi Men-of-All, and definitely the Brithini (although I don't think they would make good PC's).