I blame FFVI for me cause in VI magic was ungodly... It does like 2 to 3x more damage than any other FF I can think of and the only game where Ultima can do max damage right out of the box. Its also one of the only titles where osmose works, and works probably too well. Did Edgar just Osmose 400+ MP from that boss? Good god...
Also, the spell effects are quite nice and in the older games, magic tended to cut through more defenses. Vivi himself is also pretty ungodly in IX. He doesn't really lose his pull until Steiner gets his full weapons and if you are anal enough to max Thievery and Freya's Dragon attack...
Blue Magic alone tends to always be worth the trouble as you either get elemental spells that are far better than noraml magic (VII), uncommon elements that most enemies have no defense against or are weak to (V and VI) or just uncommon spells that do unholy things... (VII, IX, and TA series) Blue Magic is one of my favorite mage classes and I'm still annoyed the class sucks in VIII and X.