Don't do it with regards to leveling. It'll be about the same, although the 60-70 experience is probably a little easier with a paladin to tank instances, but kiting works too.
Think about end-game goals.. if you love PvP, definitely roll 5 shammies. My pally is practically useless in BGs beyond buffs, occasional heal, a stun every now and then, a consecrate for distraction, and as a steady meatshield.