This is from the EU armory, but I'm assuming the results are quite similar to a scan of the US armory. Pretty much explains why I grin every time I see a hunter team as my opposition on my warlock in the arena.
From a warlocks perspective, hunters are an absolute joke. They are very easy to los, very susceptible to CC, extremely easy to mana drain (Small mana pool, takes very little time, and they're pretty much worthless without mana), and the pet is very very easy to kill. If they have no priest or paladin, then they are ridiculously easy to just dot and hide around the corner while they rot.
I can do 8000+ damage to them with instacasts, and they have to just take it, or hope for dispels, while I run back behind a pillar.. They can't really chase me around the corner, because close range fighting is not their forté. And if they stay at range, they are ridiculously easy to LoS. You can't send the pet in, because he'll just get killed behind the pillar.
Combining those factors, hunter usefulness is extremely limited, especially in 2v2/3v3.
In addition, the shots and abilities hunters have carry a rather hefty mana cost considering their relatively small mana pool. They also have basically no period where they are getting the 5s rule of mana regen, either. Flares, traps, aspects, hunter marks, shots, stings, melee abilities. They all require mana. If you aren't shooting someone in ranged combat, you're kiting them and changing aspects/wingclipping/trapping, and if you aren't kiting, you're doing a shot rotation. In fact, the only time you REALLY get time to regen mana outside the 5s rule is during a stand-still shot rotation, which is also when you want to be doing the most damage possible, so it's not an option there either.
This holds true in pvp and I've noticed it while leveling as well. I really only get time to regen mana during a fight while standing and shooting a mob. If you're doing damage on the move, you're using something that costs mana, whether its changing aspects, wingclipping, concussive shot, etc.
I know I've played a warlock for quite a well, but I've also played a lot of other classes in this game. And I'm telling you this: Hunter mana issues are SEVERE. Their mana consumption is bad, and is rivaled only by their horrid mana regeneration.
They are the absolute worst in efficiency in the game IMO. Aspect of the viper is not enough. They need a lot of their skills revisited with mana costs. Some skills need to have mana cost just flat out removed. Feign death, aspects, hunters mark, flare (reagent cost instead IMO) possibly even traps.
It needs help. It really, really does.
Also, the aspects and how they work are a pretty big problem.
Aspect of the cheetah is pretty risky to use. Right now it's really only great for chasing down runners when you can't afford to mount, and you're sure you won't be hit. To be honest, it's times when I'm kiting without fear of being caught, or chasing someone down that I wish my mana regen was going up. However, just switching to cheetah costs me mana, and mana regen. Also, stance-dancing as needed on a hunter isn't a lot of fun for several reasons. A) It hurts my mana/regen B) It costs a GCD, which means I might not get that critical shot/ability in in time. Stance-dancing on the hunter sucks, but it's very fun and useful on a warrior. My mana bar is basically penalized for me reacting to the situation and instantly picking the right aspect to be in. It was a great feeling on the warrior when I learned how to bind my stances to keys and react instantly depending on the context of the fight. You know exactly what I mean on this. Hunters trying to accomplish this same play style just don't feel right. It feels sloppy and and unnatural. The mana cost and GCD need to be removed.
Another idea that I was actually tossing around with cham a year ago on this issue was requiring certain shots to be used in certain aspects. You'd have to be in hawk for aimed shot, stings would require viper, etc. But then we thought that would require way too much reworking of a lot of spells/levels, so we figured a bonus would be better instead of requirement, or just a changing of aspects all together.
I.e. Hawk = 10% increased ranged damage, but 5% increase damage taken.
Viper = Double mana regeneration, stings cost no mana.
Monkey = Increased dodge/parry, reduced ranged damage
Beast = Decrease damage taken, pet does additional damage, increase melee damage done. (For when you can't escape melee)
Cheetah = Reduce movement speed bonus to 20%, and remove daze effect when struck. Increase mana regeneration (including in combat).
Keep in mind, these aspects would cost no mana and no GCD to "shift" into. This gives the hunter much more flexibility to the situation.
Flexibility is the key issue here. Warriors have it. Warlocks have it. Priests have it. That's why those classes do so well. It's not necessarily damage done, or amount of shadow bolt damage. It's the bevy of class options that allows them to react to a multitude of situations.
I honestly think something that drastic is needed to save this class, especially in smaller formats. A lot of the basic mechanics that are currently existing for this class are too limiting and don't allow for enough adaptive options for the player to take advantage of that other classes have. Their flexibility isn't very good. It's basically kite until you can spam shots on a snared/immobile target until you're OOM, and until something pretty big changes, that's the way it's going to be, MS shot or not (which would only really help in 5v5, not 3v3/2v2, assuming that the shots current limitations stay as is).