While BLU Mag Skill does really work, you really have to think of it as BLU magic farming as proccing a TH. Its math mixed with a lot of luck. Regardless of the hours it takes for a spell to be learned, I've always had fun farming them(after 50 of course). It's more fun learning with a friend because of the 'oh sh!+" moments. For example, my PLD buddy and I were farming Blazing Bound in La'theine and we were moving through the group casually until we were in the middle of their spawn camp. Sure enough, they repopped and linked. Suddenly 5+ mobs each casting Firaga III and them spamming Blazing Bound at least 2 times a mob. Many Head Butts, Embraces, and Ramparts later, we were able to get out of the camp to a free zone after killing roughly 10 of them at once. Did I learn the spell after 20 or so Blazing Bounds?
Nope.
Did I have a hella good time?
Hell yea and my pally friend was laughing all the way.
You can make spell farming fun or not, its up to you but just know that it's 90% luck 10% gear. Kinda like getting the rare drops with Treasure Hunter.