All the responds here are like "hur dur, he is fed that is why he can 1v5 and you not able to kill him hur dur"
The real question is, what is his counterplay?
A veigar gets fed? Ok, he bursts you down so dodge his abilities and hope you don't die from his R.
A syndra gets fed? Ok, send your assassin to do the job or just stun her and she will go down
A vladimir gets fed? He outheals even when he is grievously wounded, his w allows him to take no dmg, his q and e have a 3 second cooldown so he goes urf on rift, he has zhonyas so in a fight when he goes low he will ult your team, zhonyas and heal back full (if that interaction was removed it would be a serious and useful nerf and that is all riot has to do) and you can do 2 things to counter a vladimir who knows what is doing 1. Ctrl+F4 or 2. /ff in chat. That isn't counterplay riot and the used to know it but right now, they have to nerf amumu instead of nerfing such obnoxius champs.