Ekko is really poorly designed

26 games with him. Every single mid match up relies on the enemy playing poorly; there is not a single favorable match up. I'd almost go as far as to say most match ups cannot be won unless the enemy is severely underskilled. This entire champion is built around your opponent making huge, glaring mistakes. If they play okay (not even good or great, just okay), you can't really do anything.

Aside from that, his late game is terrible. He cannot even kill a glass cannon APC/ADC unless they're in his Chronoshift, while they can 100 to 0 Ekko in 1-2 seconds, compared to the 4 seconds it takes for his Chronoshift to get into position. He dies before he can use it, which leaves him at the mercy of the enemy playing poorly and walking into it.

Even if I land a stun on an enemy carry as full build glass cannon, it doesn't matter, because they'll get out and kill me before my Chronoshift gets close enough to finish them.

While the concept is cool, it doesn't really work in practice. A champion that's based on your opponents playing like they belong in Silver V and stealing kills is not well designed. This is another blatant example of a designer going 'Hey, let's use this super cool idea with no consideration for how it will fit into the game.'