RDruid/Warlock will beat RDruid/Hunter about 90% of the time if they play it right. Just wait til ~35-40% dampening and then fully DoT both with double Dark Soul and there's basically no way to heal through it.
It's also possible for MW Monk/Combat Rogue to win just by blowing up the Druid in the opener. That usually only works once though when the team isn't expecting it, if you fight the same team repeatedly (which you do at high ratings because hardly anyone queues over 2300 it seems) then you basically should just win one and stop.
Other than that though, yeah RDruid/Hunter is pretty much invincible, it's basically impossible to lose to melee teams as that comp unless the Druid gets globaled.