Kassadin
Guess it´s about time to confess the "rework" didn´t change anything...infact it just made it even more important to counterpick Kassadin than it had been before the "rework", as there´s just no way to harass kassadin away from getting farm ever for an AP-Champ now. And besides running an AD-Laner against him you also still need a solid plan to end the game by min 40-45, as his lategame is pretty much untouched due to keeping his scalings far too high.
And he wouldn´t even be hard to fix...just make him a goddamn melee already, forcing him to stay in a fight and autoattack (more than 1) to deal dmg - instead of allowing him to be influencial enough from the outside with e/q and r to some degree...only closing in to savely burst someone down or if there´s no chance for the opponent to retaliate due to the shield.
As it is now...the pre-"rework" Kassadin had been more healthy for the game overall.