How Could We Make Meaningful Use of MP?

[Shurrikhan]

Okay so to be clear, you are saying that using MP to cast certain buffs/debuffs would then give reason to reduce the cooldown of the skill? Because I am not seeing how giving some skills an MP cost would allow them to be cancellable, unless you just mean they could be recasted and therefore have their timer reset.

I would assume it'd be because the core ability or abilities (where mutually exclusive and/or alternated, such as through dynamic MP costs) would have MP drain costs, and that drain would end up cancelling the buff, such that you can refund the remainder of the buff, having effectively only wasted some portion of the initial activation cost.