Being a skilled ret pally is extremely gear dependent. I would recommend going shockadin if you want to dps, which is a combination of ret + holy. I had a guildie who tried this spec. We ran a 5 man and he out dpsed our rogue and mage by over 10%. However, he had been collecting gear from kara and pvp so he had mostly all epics and roughly +1000 spell dmg with buffs/consumables. But really, a holy pally is still much more viable in a raid 99% of the time unless you got the gear to dps.