My ultimate 10 boxing I think would be a bit different
Tanks
Pally & DK - DKs have awesome snap threat and the best AoE for more then 3 mobs. While they dont have the tricks of Pallys they do have Death Grip & Strangulate to take care of those annoying caster mobs.

Healers - Damn this is hard. My main single toon is a Disc priest so I think about healing a bit more then the rest
So
Disc priest - Dedicated Tank healer, would have a cast sequence for heaving incoming damage fights to use shields, penance, Prayer of mending when on cooldown and fill in the rest with flash heals.
Resto Druid - HoTs on tank and on the people taking the most damage. Harder to manage but if you need to move your healers they can keep on healing.
For a third I am torm between a Holy Priest - Raid healer, Circle of healing, renew etc etc or Resto Shaman - Chain heal FTW, totems, Earth shield, etc

Could maybe sub out Disc Priest for a Shammy and have chain heal in a cast sequence.

DPS
2x Hunters
1x Warlock
1x Mage
1x Boomkin

Mage has focus magic, polymorph, Int buff, Frost nova, and decent DPS while moving (Assuming Arcane spec).