While I agree with your sentiments that skills more akin to limit breaks and overdrives would be nice to have, I'm not sure if the proper course of action would be to add yet another resource management system into the battle system.
Couldn't you achieve the same results by introducing limit-break-like Weapon Skills that cost 3000 TP to use?
Additionally, if these "limit breaks" are too powerful, it would be very detrimental to game balance. I'm sure you remember how overpowered some of those limit breaks and overdrives were in their respective games.
