On my last day before kassadin's olafing I trashed a toxic Zed in lane.....

Good night sweet prince, you will be missed :(

What role will Kassadin even fill now? As assassin goes his burst is probably the lowest in the class, obviously to balance out his identifying mobility. Yet with that take a signifigant nerf what is there still to offer? Kassadin's R is at least a blink so his ability to go over walls is more forgiving but beyond that its really hard to justify using him.

You already have his sub-par laning, his delayed power spikes based on his build, and the risks inherent in being a melee/short-ranged character. What do you get in return for all these costs? The single most mobile champion in the game. Except now they've put a dent in that too.