Glacir

I understand how that could work for henotheists of Fronela, Ralios and Kethaela (especially if treating Arkati cults as Rune cults and not some philosophy schools or cabals teaching sorcery), but that feels kind of wrong for "true" Western societies. Both Rokari and Hrestoli as far as I remember forbid the veneration of "pagan gods", and Rokari forbid even the veneration of Ascended Masters, which means that for Seshnela you wouldn't even be able to disguise a Rune cult as a saint's cult, and commoners will have to do only with Spirit magic. Also, as Joerg said,

In RQ3, some of the regions (Safelster and Jonatela, Kingdom of Ignorance) grant all characters access either to Divine Magic or to Sorcery. How would one adapt that into RQ:G ruleset? I've been thinking of allowing sorcerous characters (= Malkioni/Arkati worshippers) to receive the benefits of Philosopher occupation from RQ:G (understanding of one Rune and one technique and three spells) instead of Rune Magic, and probably Philosopher skills instead of Cult skills, but that will probably caall for a need to create a specific occupation for dedicated sorcerer with access to more Runes and techniques, like Malkioni and Aeolian wizards described on p. 389 in RQ:G rulebook.