Zilean "Rewind" Concept

What if we reduced the active flat CDR benefit to 5s and added a passive effect that increased the ticking cooldown of spells by 0.02s per 10% CDR he obtains? I think that would add a touch of essence to his ability to control time, what he is known for. I don't consider the current W specs to fit that enough.

This is just a concept, no harsh feelings