You guys can also ask Xynin about his experiences, he has SCH and BLM at 75, I think his BLM is fully merited, and has very good gear for both. While talking with him, his general opinion has been that if you're just going to nuke, might as well go BLM. The potential for aoe buff's, on the other hand, makes it an insane support job by far (SE updated en-spells, now only based on caster's stats). Also, when doing the math on magic skills, dont forget the 2 af pieces give I think +15 to each skill within dark arts or light arts, while one or the other is active.