Ekko IS easily countered. You have no idea how badly Leblanc and Fizz will shit on him. He did have some ridiculous stats when he first came out but there are very clear weaknesses. First, he's very mana hungry, throughout most of the game, especially now that his ult actually uses mana. His Q can be easily sidestepped and you can work around getting stunned by his W. Most people just need to use high mobility champs against him (or, as some like to call it, broken vs broken) and have a decent knowledge of his abilities. You can avoid receiving damage from his ult by knowing where his little ghost thing is (I don't remember what its called lol srry) and keeping distance from it. Also, he has fairly long cooldowns which can be easily abused and used against him in the laning phase, as well as the fact that he's melee so you can zone him away from your minions and if he uses his Q to farm, he will be oom very quickly.