And what class + spec do you play? Because as a melee player, I can't pressure a tank enough in arena so I only have two targets I can choose to kill. With the tank in arena, he just does consistent damage enough to warrant healing from your healers while having a ton of CC options to prevent you from killing their healer, god forbid its a guardian druid that is immune to most forms of CC itself.
A week or so ago, I was on an alt fire mage, Q'd a skirm, got into a 1v2. Both players however were very bad, the first guy died like a fly, the second was a guardian druid... Who just tanked my damage and slowly widdled me down. I lost to a bad player, that played bad, just because of his spec choice, if he had been any other druid spec, I probably would have won that game.