Kennen needs a buff
What this champion needs most is some CC immunity on his E.
He is shut down or avoided by nearly every enemy in this game. Combine Summoners like
and he is the easiest champion in the game to ignore.
He is full of other problems like extremely low damage, high energy costs, low energy recover, long cooldowns, low range. He is completely unique in that he has to run through multiple enemies in order to deal his damage, yet has horrible mobility and zero CC protection to do it. It makes no sense.
This champion is just bad overall which is why he is hardly ever played.