I recently lvl'd my paladin to 70 doing retribution, at which point I switched to prot.
Instantly I got invited to a crap load of instances/groups. Two of which were a main tank for a kara group (which i decided not to do at the last minute), and main tank for normal UB.
Before tanking for a paladin was one touch idiot button and was fairly easy. Now it's 3 touch and very easy. I took on pulls of like 6-8 mobs (we had no cc) the healer kept me well above 3/4s hp and thus spiritual attunement kept my mana up I never lost aggro and produce a mega amount of threat while doing good DPS.
I love the changes to prot pallies. I used to be prot pre lvl 60. I look forward to tanking kara at least once before wotlk.
why did I post this you ask? Idk, maybe take a look at my gear (Diestructo on shu'halo) give me some suggestions, or talk about tankadin or tanking experiences or whatever.