Kassadin New Passive

I was thinking that even though his passive is good with dealing with mages, but makes him useless against a yasuo or zed. Also, I wanted to flesh out the terror of a roaming Kassadin, as with a good gank with kassadin it is easy to get a kill:

NEW PASSIVE: Void Stone - Ignores Unit Collision, !5% bonus magic resist and 10% bonus armor. Void Sentinel - Kassadin can passively mark turrets and wards with void energy, granting him 5% bonus damage when in range of the turret or ward. When kassadin leaves the range for an extended period of time, he will gain extra movespeed and cause his riftwalks to gain extra range for a short time.