I play a ret pally and in PvE yes, we have an advantage. we can do it all. But you will find that DoTs and Pmorphs are hated by us and mages will always have the most advantage, frost I would reccomend. roll that and enjoy the PvP and instance ownage.
Mimmn Level 80 Retribution Human Paladin EU Hellscream <Horde Hunterz>
Retri paladins are NOT overpowered anymore... They have had a long string of nerfs, which were meant to balance them in PvP, but affected PvE damage badly. Blizzard has also not given retri paladins any offensive PvP utility, eg. MS, silence, interrupt etc. which, though they can take on a dps, it makes killing a geared healer near impossible.