If the mage archetypes are remotely based on MtG, as they seem to be, having the Green Mage be optionally Arcane/Divine seems to make a good deal of sense to me? Perhaps with Divine/Wis stat and Arcane/Int based? There's ample examples in the lore for both depending slightly on the setting.

And as I happen to like overgrown lizards, are dragons suitably overpowered? (They should be unabashedly OP IMNSHO. No sense to them otherwise. Like, dragon ~= elf caster, except it's also an ogre and not dumb. Class+race combo is a brilliant way to go about it definitely.)