Honestly, my problem with Ekko isn't even his ridiculous kit (well, not primarily)
It's the sheer lack of clarity you get when facing him. Ekko brings absolutely LUDICROUS damage and utility to the table...and as an opponent absolutely none of it is intuitive. I've not got a chance to actually buy him, but I've read the stats, I know the ratios, I have seen the champion spotlight and a couple gameplay videos, and still when playing against him nothing makes any sense.
Examples:
-My last game against Ekko I played as Graves. I was fairly low HP, but had mana and my ultimate and there was a fight going on. I figured that I would hang around just a bit to try and throw an ult and help my team clean up. Ekko throws his little skillshot thing, and it comes up short. I juke back a little bit, staying out of the visual indicator I can see on my screen... And then when it returns to him the damage AOE for some reason extends PAST the visual indicator in a little "poof" of damage, which killed me. there is ZERO clarity in that spell, no indicator what it's going to do, him throwing out a thing that slows and chases you and then comes back with a little invisible poof of damage is just bizarre. Wasn't Zilean (the forgotten time-based champion) JUST changed and given a whole rework because his bombs (which had a timer telling you exactly when they'd explode) didn't have enough clarity? It's a BOMB, you figure that a bomb is going to have some kind of AOE with the explosion particles and all that, it's intuitive. And yet, it gets an indicator and Ekko's little thing does not, so you have no idea when it's going to explode or how long.
-And that brings us to the bugtastic clusterfuck that is his stupid ultimate indicator. Great concept, absolutely stupid implementation. For one thing, MAKE THE DAMN THING VISIBLE when ekko himself is in a bush. That's called having a trade-off. You know, like how a Rengar who's sitting in a bush completely invisible turns on his ultimate which is a STEALTH and suddenly enemies around him become more aware of where he is because of how powerful an offensive tool that ultimate is? The way the mechanic currently works is just nuts. When Ekko is juking in and out of fights and you're trying to watch for the stupid "batter up" tell for his giant 2.25s AOE stun with .8AP Shield on a basic skill his little ult passive is popping in and out of existence, glitch-dashing from bush to bush and the worst part is: IT DOESNT EVEN TELL YOU WHERE THE ULT DAMAGE AOE IS GOING TO BE. Like, at all! It's an AOE burst spell with a 1.3AP ratio and there is absolutely zero indicator of where it's going to be! This spell is like if Riot decided they were including the invisible nid spear bug as a feature for the champion! While we're at it, why don't we hide Nid/cait traps, zac blobs, and zyra seeds while those champions are not visible? Sounds like the same level of counterplay to me.
-His freaking passive. Not only does he have the enraging annie-esque ability to just insta-trigger it with a neat little button mash, quick, tell me if you have two stacks on you or one? Braum gets this HUGE indicator for the possibliity of a 1 second stun. Ekko's passive is an 80% slow, 80% speed boost for Ekko, and has a .7AP damage ratio and it's got this tiiiiiiiny teeeeeeeny indicator that looks practically the same at 1 or 2 stacks. This thing is an escape tool, a chase tool, and burst all in one, and Riot gave it a wafer-thin blue line, because clarity. Oh, and it gets triggered by all of Ekko's magical particle-less abilities :^)
-His W. Now, as we talk about his W, I want you to remember that Veigar was recently DEMOLISHED for having the following skill: .5 second cast delay creates a ring, enemies that contact the ring are stunned for 1.5/1.75/2/2.25/2.5 seconds, 80-100 mana, 18-14 second cooldown, no damage. Ekko's W has a 3-second windup, but you only get an indicator for .5 seconds of that. It creates an AOE (not a ring) exactly the same size that slows all enemies inside, and if Ekko enters the ring with, say, his instant blink, he stuns all enemies inside for 2.25 seconds (RANK ONE LOL) and gets up to a 300+.8 AP ratio shield. Oh, and take note that if he performs this combo then lands one autoattack, after the 2.25 second stun the target is slowed by 80% and he gets an 80% speed boost.
Talon got the 1-second silence removed from his instant blink for having "no counterplay". Ekko has an instant blink that comes with a wall jump that can deal a 2.25 second AOE stun and then an 80% slow.