This is funny but severely eductational in tactics, and just cool as hell.
I just got done the WEIRDEST composition of an Underbog run, that I have ever seen.
70 Felguard lock serving as tank
64 Shadow Priest serving as healer
And the DPS was my 66 Affliction lock, a 67 Frost Mage, and a 65 fire Mage.
No amazing out of this world gear. Not even Kara pieces on the 70 lock.
Our results: 1 death of the priest, to the pull of the 2 giants before Hungerfen. 1 death of the lock on Hungerfen.(who I then manage to take myself for the last 10% of health with a shadowburn crit for a killing blow)
NO OTHER DEATHS.
We took every boss out. And we made it through the the non CC'able bug hall by "Ice Kiting"(blizzard into a frost nova, into another blizzard to keep distance. Meanwhile the rest of the party AoE and DoT's the hell out of everything.)
It was nuts, but somehow it worked perfectly. We did UB in an hour, to an hour and a quarter. Oh and no TS or Vent. It was like we all knew what each other needed instinctively.
Downside: We had to shard every piece of loot that dropped as they were all leather or better, or melee weapons. Not a single caster drop.