I'm playing 2 lowlevel hunters now and then (using up their rested xp) and had a lot of fun in the 14-19 warsong bracket. They got some heirloom stuff only (shoulders/breast/gun and 2 daggers) and they basically one-shot every other player of that level. I know that effect from playing 5 mages but with only 2 hunters doing the same I can see some potential for a full hunter team.

On the other hand I have played a team of 4 warlocks + priest up to level 81, did almost all pre-cata instances with that team and I'd call that an interesting experience.

5 priests (well 4 because I got one highlevel already) are still on my list.