I just dealt with a pretty good Ekko, and man he is bursty mid-late game.
I don't claim to be the most skilled player, but where I am I usually pubstomp the enemy mid laner. 8 or 9 out of 10 times i win lane.
I pubstomped an enemy Ekko last night as Zed, going about 4-0 in laning phase, but about 15 minutes after laning phase he absolutely wrecked me and my duo partner, with a Q, E combo that one-shot him and he then almost killed me with his ult.
Was it Riot's intention for Ekko' to be able to one-shot people mid and late game? If so then I guess that is fine, but his kit is very hard to avoid when he E's to you.
His ult is fine, maybe a mana cost or more cooldown would be good, but it's fine. But this "sustained burst assassin" i'm starting to see from good ekko players is scary.