What if energy worked more like rumbles overheat?

With all the recent mana changes and many of the problems that so many have with the champs that rely on the energy resource, what if it was more like a build up similar to rumbles overheat rather then the way it works now. If you reach max energy use you become "tired" and cant use any of your abilities until counter hits zero. This would create moments of weakness and allow counterplay, as well forcing similar micro managing of abilities to mana reliant counterparts. Thoughts?