| Shaman are more middle of the pack honestly. They're not terrible and you still shouldn't ever lose to a rogue or warrior. Fighting a mage would depend largely on how the mage is spec'd. Druids should be relatively easy.
Warriors aren't too bad. It's just that they've been walking gods for so long that now that they're back down to Earth with the rest of us they're learning the hard way what it's like to not be able to win 90% of matches.
Warlocks, shadow priests and hunters are all pretty and everybody is pretty even. Between the two groups however is a pretty huge gap. | 