Some people here want their Cooldowns, which is a tool to lower spamming ‘The big guns’ (Ult or just strong skills?).
Some may claim it breaks immersion and just not natural for the setting or RPG games overall (Or just ‘lazy balancing tool’)
While cooldown may fit in with some skills (Hopefully a short cooldown), I would like to introduce another, a more organic, idea for balancing: Prerequisites
For example:
Sorceress: Do enough Lightning damage to unlock Conduit: ( You become lightning incarnate ).
Those prerequisites can be improved/hardened with skill level:
The higher your lightning damage output is, the fewer hits (And time) it’ll take to recharge - but the stronger Conduit is, the more time you’d need to recharge the skill.
I would love to hear your opinion about this mechanic.
I’ve already presented it in 2 other places and tried to take reviews into account before posting it here.
Regards,
nachuo
P.S.
Please keep the tone mature and civil 
There might be alot to experiment with this kind of system.