It wasn't a joke. I can't wait to buy him.
I'd suggest though to exercize with him a lot
I decided to play some matches for once to check him out (from Yasuo's experience I was 100% sure that with an assassin coming out every match would have had someone using him) and frankly this is what I think of him
Early game/Laning phase he actually needs skill to pull off a snowballing fest: even though you can't see his W target if not when the ball is striked, you can see the other him coming out, thus preparing yourself already (for this reason, he has good ganking/jungling capabilities, but it's very difficult to hit someone with your W in lane). Also, to hit someone twice with your Q you need to stay quite closer than you may think, making you vulnerable to ranged retalation. Lastly, he must manage his skills well or he quickly runs out of mana
However, outside his lane he was a beast. I won against an Ekko top only because I went AP Malzahar and completely blocked him from getting anything more than a Large Rod and something else when the match ended, but while I was against some Jungle/Mid/(other) Top Ekkos they were godly: in a teamfights this is what once happened
-Enemies engage on our team
-Ekko was far away, giving us time to properly damage his teammates
-Ekko uses W
-Starts running in
-Double dash
-Q that hits all our team
-Bashing the shit out of the carries
-W activating, letting him kill the carries
-After 4 seconds he freely used his R to burst our team remnants (if he wanted he could keep it to then completely turn the situation if he somehow was about to die)
-Aced
Also, it is probably impossible to catch a Ekko without risking being bursted by his W + R combo: I seriously think that chasing an Ekko with his ultimate up and enough mana to use his abilities is far more dangerous than chasing a Singed (without actually considering his slows and mobility, making him close to a damn Nidalee for that)
If you don't fuck up at the beginning and can properly use his abilities (not at their max, just properly) you're literally the bastardish son of Zed, Lee Sin and a mage