You can tank as Holy or heal as Prot or Ret.
You can quest as holy with 2h but thats meh compared to dungeon healing or tanking. Dungeon tanking for Mage Cleave will be super fast, but be prepared to drink your backside off as Prot.
As for 1h shield holy leveling that would be for consecrate grinding 2-3 mobs at once. Have I ever done that? Yes, but not on a character I leveled all the way to 60 using that method.