@RIOT: What do you think of the ulti Cho?

It can be quite frustrating to be against a cho Rabadon Rod of Ages and followed by a stuff completely tank. Cho is often very complicated to kill. He often inflicts 920 damage with his ult.

Why not put his ult with health ratio (to prevent synergy with other spells) and slightly reduce this damage.

In the worst case to damage his ult in physical or magical.

And you, what do you think?