Why Kennen is bad for the game
If you are a top laner, go ahead and think of everything you hate about top lane champs. Chances are kennen has at least 2 of these if not more. Kennen is the embodiment of everything a top laner hates. He has hard cc with range, that has no cooldown, he has a movement speed buff that has a low cooldown, aoe cc so he teamfights well (on a low cd as well), he builds ap so he scales well into the late game,is ranged, is a strong lane bully, can abuse klepto so he can get his items faster, and counters about every top laner, oh yea and he is a energy champion so he never runs out of mana.
He is beyond broken against every top laner, i first timed him against a singed top and the poor guy had 20 cs at 20 minutes, he had to either choose to lose to not having any cs, or lose to feeding me, the only actual way to counter kennen, is to dodge in champ select.
One way in my mind they could try to nerf him is they could increase his cooldown on his r, make his energy costs higher, increase the cooldown on his e (his low cooldown movement speed buff), and put a cooldown on his stun passive so he can't stun you multiple times a teamfight by ulting and running his face across his keyboard. Or another way you could nerf him would be to flat out remove him, I would be fine with either.