Originally Posted by Puschel the Soft
The problem is: In ranked games people are usually a little more committed to win, so your enemy team will rarely choose an easily counterable team (like 4 melee dps).
Lots of disables will occur rather often though.
I don't know about ranked solo Queue, but at least in premade I never encountered a really unbalanced team
You're right, in ranked games, you'll usually encounter balanced team compositions.
But this doesn't mean, that counterpicking is impossible.
Counterpicking doesn't necessarily have to counter their whole team.
E.g. it's sufficient, if you counter their Annie with Brand, because Brand has a superior laning phase.
Or if they pick Amumu, because you banned someone else, you could pick a strong counterjungler to shut down Amumu right from the start.
If they pick a Tryndamere, you'll pack 2 Exhausts.
If they've got heavy CC, you might want to pick Irelia or Gangplank, maybe take Cleanse on your AD carry.
This stuff might give you the small edge to win.