In the original game (and FF:Origins version) magic damage is completely independent of caster stats. So red mages do exactly as much magic damage as black wizards. That an magic damage isn't all that much to write home about.

This also means all the lower level spells never increase in damage making them completely useless later on. They do less damage than the black wizard's melee attacks. Combine this with the old tier based magic system and you have a character that gets to be useful for a total of 10 turns every dungeon.