I'm genuinely curious to see why not many people play 
. His ult is amazing , you can rush 
, his e escape comes in handy in ganks (depending on the jungler), and he has pretty good wave clear. So why does no one play ?
Because he's simply not as efficient as other champions such as Irelia, Vlad and Maokai. He is indeed very strong and fun to play as if you get ahead early on, but he is so extremely item-reliant that he has a very hard time if he falls behind. There's also the fact that so many people play Kennen like pussies, which results on him doing very little duringthe laning phase and especially in teamfights (for example, using zhonya's straight after you ult without using any other abilities).
requires too much effort to do well in comparison to other champions, and as for wave-clear, you are fooling yourself if you think has wave-clears before mid-game (and even then the wave-clear requires putting yourself into harm's way unless a wave-clear from say a mid-game 
). I should know why isn't played since I main him (and also 
& ). Most people simply aren't going to get his positioning nor team-formation right & they also typically don't know what kinds of compositions work best with him as well as the fact that he's not necessarily compatible with a wide range of compositions at least not nearly as much as many of the other choices. Also best played as a counter-initiator from my experiences which most people seem to lack the patience for.
