Dual-spec is your friend.
I personally leveled with 4 boomkins, i had no trouble with the rout i took, 1 feral 2 healers is quite a waste of possible dps.
On the Dual-spec note go to your trainer and get it, it only costs 10g so you can have your feral booster and your 2 healers to try them out. if you enjoy it, play it