I have been learning LUA as per GuyPerfect
In it I actually was considering a novel way to do cool downs for powers instead of time penalties use control, temperature or other effect to affect the power cool downs.
For example: Fire/Ice are quite easy you have a core temperature if you exceed the limits it shuts off the extreme powers. In other words you have a blaster (Fire/Ice) who fires a tier 1 fire attack rapidly and then hits with a tier 9 cold attack like Blizzard. I would not use a stamina type gauge to control the powers instead I would the idea in this case of you core temp is unstable - I would allow for a self destruct type power where you could double tier 9 but you have a chance of killing yourself.
This could be used in control - where you try to quickly resummon your tier 9 pet and it could be successful - or be confused as you are overly taxed and they attack you!
I would use this sort of conditional loop where you can try to do something incredibly heroic - and possibly fail spectacularly or win in amazing fashion.
I would label it as CORE strength and onscreen you could have the message your core is becoming unstable for those with blaster type powers and for those with control you could use - you are becoming confused or some such message for each AT. I dislike the use of Stamina in a hero/villian game as it seems way to limiting - where you often are able to try one more time to go beyond normal into super human.
Just floating the idea out there.