ToME WikiMagic (a.k.a. Thaumaturgy) in Bas-Lag should be quite different than in ToME. The best way to handle it, IMO, would be to base the system on sCthangband's "spirit magic", with groups of spells that have to recharge after a certain amount of use. Unlike said sCthangband spell system, calling on external spirits would not be involved, but there should definitely be a potential for backfire; also, more powerful spells should have nasty effects on the caster, such as wounding, blinding, or hallucination. Player characters should not have spellpoint counters, only HP and sanity. Most spells should probably have an HP cost.
(more to come)