I would go dual-spec, resto for PvE but feral for PvP.

You can mix it up, and see what works best.
But many have pointed out, healers are focused on, and you'd only have your one toon healing.
Not sure if resto, without tree form, is at all viable.

I'm guessing Feral + 3x Rogues will be better.
As you have ressurrection if you need it.
And then you have a full stealth team, that will be brutal with IWT spam, stuns and such.
Excellent for rushing towers/bunkers, or recapping them too.