Ok, I read the entire OP.

Well it's certainly a good idea. I'm a bit on the fence about the implementation of the Ninjutsu spells. Why not just put each of them in the same as a CON has the elemental spells? And I would suggest having those just use MP. You'll have plenty of weapon skills for burning TP. I think if you take the Ninjutsu spells, one weapon skill per element, the en-spells, and implement the SAM battle stances, you have a pretty good formula for a new class.