It's not argued by many that BM and Survival need some help. Right now BM is actually the lowest physical damage spec. Survival is third from lowest, only beating out BM and Unholy DKs. Put another way, ALL melee dps are better off than BM and all but one is better than survival.
Looking at those two specs you'll find that they gain most of their damage from attack power, particularly BM which also has a specialization buff to it's attack power.
On the other hand, MM doesn't gain as much from attack power. A lot of it's damage is based on weapon damage so it wouldn't gain as much of a benefit from the attack power buff.
Blizzard, this is a REALLY stupid simple fix for the discrepancy between the hunter specs. Not only would this really help BM hunters and help SV hunters a good amount, it also wouldn't do nearly as much for MM hunters.
On top of this, hunters are about to be passed by elemental Shaman, putting us at 8th place, beating out DKs (which will pass us with the AP buff if we don't get it) and retadins, so honestly all hunter specs need a buff anyway.
I'm not saying that we need to be top dps, but considering all we can so is dps can we at least be competitive at it?