The spellcasting in dragonage, as I've said, and shall continue to repeat, really, really, really, should be done with the Spellpoint system. There's even rules for Vitality, spellcasters becoming more and more tired as their spellpoints are used up. This means that spellpoints are also restored as a mage would become less tired. As the generic Mage class hasn't been adapted yet (and likely never will be), I think Sorcerers fit best for Dragonage, specifically those of the Arcane or Destiny bloodlines, but, in theory, the others may work, with those just being the most common.