Ekko counter + tips | Hope this helps!

Ekko isn't strong if he doesn't position himself properly. Ekko focuses catching people out of position. He is not like Zed and Leblanc where they just point-click and annihilate their target. Ekko is more a champion that has to time himself and position himself properly and knowing the risks that come with what he is doing. Yes his W grants him a big shield and stuns, but he is risking himself to go into that bubble where lots of enemies can be positioned. Going into the bubble grants him rewards with his shield and stun, but to get that kill he needs the Q and passive. His ultimate is used in two ways as well. One way being doing insane AOE damage, but having no escape, the other escaping, but doing less damage out put. He kind of gets rewarded using his ult on people instead of escaping that is why it is high damage. It is different from a Zed ult because Zed goes in does damage and still gets out. Ekko either does damage, or leaves. So countering him is very logical. Here are some tips:

• Once an ekko goes aggressive with his first E dash that's a very predictable sign where: 1 he could have thrown his W at you so walk left or right 2 He is about to throw his Q so be ready to sidestep or avoid the return damage.
• Pay attention to when he positions himself, he usually walks up to Q and uses his E in the process to proc his passive, this can be avoided by simply not getting hit by Q OR using ranged champions against him I.E. Azir.
• Ekko is going to wait for you to make the wrong move. Again going with the first point, its very obvious to know whether an Ekko has thrown their W because they will go overly aggressive
• If he procs his W, don't trade him while his shield is up
• Stay away from his ultimate trail. This probably the easiest thing to do. Go opposite directions from it, don't follow it or you will die. Again another reason why Ekko punishes you for being out of position.
• Once Ekko goes in and he misses everything, Go extremely ham at him as he has nothing else to do besides ult away
• Don't get hit by return Q -_- . Walk away from it.
• It is sooooooooooooooooooo easy to know whether an Ekko's ult is up or not :| Just find his ghost, if it's not there he has no escape
• Don't chase an Ekko if his ult is up
• His W takes a long time to pop up, use that as your advantage

Tl;Dr His kit is designed to punish you for being out of position. If you avoid all his abilities you will be fine. Basically it is like, If you out position him, he can't do anything to you because he used all his abilities which he missed earlier. His main damage source comes from his Q and passive so pay attention to that. Can't say much else. Hope this helps!