i dont see the problem with ekko tbh
sure his damages are a bit too high. nerf the ratios. thats it. even with that big damage he is so incredibly predictable its just about about aim for where he's gonna be.
champions i found have an easy time with ekko
(can't rewind if you get deleted by 400 ap + 80% of your AP r. cage also stuns).
(can dodge stun/ult with her r)

most bruiser duelists can beat him, and most mages with reliable poke/lockdown will crush him. not to mention the tanks are a nightmare for him too. a lot have MR steroids, shields, and a ton of cc.