Double Shockadin 2v2 team might have some potential in WotLK:
http://www.mmo-champion.com/talent/?...00000000000000 would give both Paladins an obscene amount of mana regeneration, coupled with Spiritual Attunement. Overall, it certainly feels like Shockadins could have some serious potential in PvP.
In a complete different train of thought: I've been thinking about the HoSalv changes and the possibility of using a Sheath of Light/Holy Guidance/Judgement of the Wise build (
http://www.mmo-champion.com/talent/?...00000000000000). Holy Shock/instant Holy Light bots, casting HoSalv as needed and spamming Judgements to give good returns to the raid with Judgements of the Wise. Reactive Healing - Holy Shocks to be used either offensively or defensively depending on healing requirements - and the ability to instant cast Holy Lights every 15 seconds. Would certainly turn Holy Paladins into buff bots.
And with the "second" talent spec that Blizzard talked about, a simple talent change could turn you the Holy/Ret Paladin into a more conventional Holy/Prot build for certain encounters.