Kassadin

So I see people say ''Kassadin is busted wtf'' but in my PLAT games he's not even a big deal? Even I play him and it never turns out to be an easy late game win ''late game kassawin ezpz''

and i know about masters+ he's an issue they say but i see people waste their bans on kassadin when they can instead ban Irelia/camille/akali/etc etc in Platinum.