Your TMG is really limted when it comes to skills.
I didn't write all the ideas in my head, just a few. I mean if I was to write out everything, it would include stats, alot more Spells, Weapons Skills available for Time Mage use, Weapons, the list goes on. I just wanted to convey the concept really. I do agree if this was to be included in the game a lot more Spells/Abilities would need to be added.

Return is a pretty crappy 2 hour; the main problem with it, being that it only works on the TMG, which really can't do much in the way of support.
Maybe so, but it could do wonders in the way of gaining back exp from death. Combined with /WHM you could Return back after Death and Raise the party after Lv50. Who needs support when you can do awesome stuff like that?

Also, how does Demi work? If it deals damage by percent, it would be way too overpowered.
Certain enemies are immune to Demi, generally bosses with vast amounts of HP.