A Pally tank can hold several mobs stick to him. The Mages' CC helps with a lot though and makes runs go VERY easy. With my 3 Mages, even groups of 5 mobs gets shrunk down to 2 and I can take my time and easily clear the group.

With Mages though, they are VERY squishy.

If I had to do it again, I would probably go with a Paly Tank, 2x Mages, 1x Druid and 1x Shaman, or Paly Tank, 2x Mages and 2x Shamans. Or Paly Tank, 2x Mages, 1x Priest, 1x Druid.... BLAH... I would swap out one of my Mage for something else just for additional buffs (another Shaman for stacking totems, or Druid for their buff, or a Priest for their buff)..