Probably not. He needs a kit rework. By nature of how he works, he's always going to be too strong or too weak.
he's as balanced as he's going to get right now. i think he's in a good spot as a counterpick to LB or Ahri. He is actually what he was originally intended to be, the anti-mage. He counters mages right now. That's his job. If you're going to pick LB or Ahri and you don't ban Kassadin, that's your own fault.
And while his laning phase vs those champions is still very strong, he gets smacked hard by other champions (ie not mages) and pre-6 ganks.
Kassadin will never be more balanced than he is now.