Tried a Yogg Saron Freeze Mage yesterday and got shit over by Control Pallies. Pyro + Equality (x2), all the healing (Ragnaros, Lightlord does a crap ton of healing), Peacekeeper + Stampeding Kodo, Sylvanas, Cairne, Tyrion, and N'Zoth. Had no chance with Freeze Mage.
Also lost to Control / Combo Warrior (Frost Giant + Charge + 2x Faceless) and Combo Priest (Velen + Embrace the Shadow + Flash Heal and Mind Blasts. Was pretty salty about both losses, but this was at rank 20 and I was trying (and failing) to make Freeze Mage work and I should've known a big combo was coming.