Is Kennen sup still a thing?

Its not a thing because other supports offer so much more. Such as Karma... she has sheilds, a lock on stun, great damage and can have lots of sustain with using her ult and her stun on a target. What does kennen have? some damage.

Hype died down.

It still works, but sheep just fled to something else.

he's alright, but it's really hard for him to get damage which is part of what makes him good

I think in some regards he's even better then he was before with the ult hitting minnions if the jungler wants to try and tower dive he's gonna get melted. The problem he has is that people are still trying to max his W which the unit reduction doesn't sound bad on paper crippled his ability to harass the laners with thunderlords. He can still do it, but he puts himself more at risk. He's by no means bad though even with the new athenes destroying some of his strength.