Are we gonna see more kassadin buffs?

Not unplayable. He's an assassin that can't do much in teamfights but is great in 1v1 - but not in laning early game.

probably because he still has the lowest base damages and scalings. the only time i see kassadin doing well is when someone idiotically feeds him few kills in the first few levels.

hes only good as a counterpick to lebullshit and even as that he is trash pre 6 and doesnt really do meaningful damage until a couple of items

I think hes fine, hes really good vs mages, and once he hits 6 he becomes a roaming god. I think Riot's done the impossible and finally made Kassadin balanced.