skill readiness vs energy available

As a warrior you have many skills that can only be activated when you have enough adrenaline. When you dont have enough adrenaline, your skill button is grey'd out, so its obvious that its not ready. As your adrenaline builds, the skill button slowly brightens up...

Id like to suggest that the same "grey'd out skill button system" is also implemented for skills that require ENERGY, not just adrenaline related skills - so if you dont have enough energy to cast/use the skill, the skill button should be grey'd out. As your energy regains the skill button can slowly brighten...

I know that during battles this would really help people to see which skills are available and which skills are close to being available again.

What does everyone else think?