If prot (tank) I dunno why someone would choose that over ret, if prot/holy (healer) You could just faceroll to 2k rating 4 sure (If you know how to play wow any good).
I do arena to have fun (playing the game and get entertained) not to get the latest gear... Thats why I got 1.4k rating with my mate whos arcane mage. I could have 2k + if I went with this R-druid that offered me to join his 2v2 team. So If you want to have fun I suggest just going with the spec you like the most, wanna get the best gear available you should go do 3v3 instead of 2v2. Still wanna get S6/S7 by doing 2v2? Go prot/holy and let ur DK stay Frost and just run around and heal him/her. Simple as that I guess.