they intentionally nerfed the priest heals to counter the increased healing from pvp power to leave shadow as it is if i dont remember wrong.
if you barely touched your rogue ever you wont have good times playing oneLevel your rogue would be my suggestion to you.
also if by pvp you mean more like doing lots of random bgs and only doing bare minimum cap in arenas, ranged classes have easier time in bg setting most of the times unless you run with a pocket healer.