From my (only pugging) experience I prefer my prot paladin for FCing over my resto shammy , sure the movement speed is great but most time I find myself needing to pop out of ghost wolf to top myself up , most pugs after the first flag cap will have dedicated peeps defending especially hunters.After a few debuff I cant kite in ghost wolf form so there again I lean towards my prot. Most of all I really value the amount punishment I can endure in pugs, I'm being bursted down by two rogues ,hunter and priest , teamates nearly there to backup , I need to surive for half a minute , popping battle standard , lay on hands, they have about 7000 hp to burn through without me putting out a single timed cast, priceless !
Also as prot I have really good burst to get those small efc gank squads down , not to mention silence.