The Ret's are proven with a DK tank.

Other melee lack healing, unless you go DK Tank + Healer + 3x Melee.
Feral Druids do have some heals via Leader of the Pack, and can all heal in caster form.

I'm toying with the idea of 5x Feral Druids for a melee team.
Possibly with Worgen.
Leveling they will all go Cat.
Possibly dual-spec one Tree.

I already have a feral bear on my mixed team.
And a 5x Boomkin squad.
So would like to keep my future melee team different.
Already have an instance team, so probably wouldn't need a bear.