I used to run a melee team in PvP 5 boxing but it got AE'd down too easily. Even 3 people can AE down a 5 boxer who is running a melee zerg all stacked on top of each other. It becomes impossible to heal with 1 healer. Well, unless you are running something really silly like 5 blood DKs.

Numbers unfortunately matter with this kind of setup. Obviously 10-15 people are not going to take down a 40 boxer who has 10-15 healers responding with heals in kind.

I'd rather a setup where you don't stack on top of each other. A small setup like 3s arena with a melee cleave is best suited to split your melee up routinely. So they can't be AE'd to death. Or run something like turbo in WoD with a huge wall of defensives.

Anyway that's my 2cents on the subject. It can be done but you need a huge number of accounts to make it work.