I actually really like Prot paladin in vanilla its my favorite spec to tank on. It drives me nuts tanking on a warrior or druid because of the lack of AoE threat. Sure, they consume a lot of mana and need to drink… but smart seal and judgement juggling + consumables can really make up for most those problems while leveling.
As for Ret… well… i advise waiting 6 months then TBC goes live and Ret is in a better place.