What is it with Silvershard Mines?

I've done a lot of random battlegrounds, both for honor points and for achievement points. In fact, when I first starting seriously going after some achievements, one of my first forays into it was Alterac Valley. That taught me that going after achievements required 1) a decent plan to make sure it would happen and 2) the willingness to do multiple attempts to get it right. A lot of them are RNG, but you have to be ready for the opportunity when it comes.

Anyway, I got fairly good at random pvp by the end of it. It's a completely different beast from high end arena, but among the unwashed masses I could affect the outcome of the game a lot of times. Surely I am at the mercy of the rest of my team and theirs, but from one what you can expect, I think my track record shows I am either getting ridiculously lucky, or a common factor in performing above average.

AB: 370/492 (75%)
Twin Peaks: 193/272 (71%)
WSG: 398/569 (70%)
Strand: 291/429 (68%)
Gilneas: 246/366 (67%)
EotS: 260/392 (66%)
Kotmogu: 102/158 (65%)
AV: 199/316 (63%)
IoC: 157/248 (63%)
Silvershard Mines: 71/144 (49%)

Except for Silvershard Mines - what the fuck. Especially lately, my win/loss ratio has been atrocious as I go for 100 wins. For the most part, this generally suits my elitist attitude that the bigger percentage of the team I represent (the smaller the format), the more my performance is going to affect the outcome. And through experience and good play this should generally be a positive contribution.

Ok, I know, I'm not being entirely fair. My win ratio is well above 50% in all but SM, which is more than anyone could expect if things were balanced. But they aren't balanced, and for good reason. Don't get me wrong, I think classes are fairly balanced, especially in BGs, if you consider all BGs combined. But player skill is not balanced, and games are not tiered, so it is a reasonable assumption that the better players have more of an impact. For those of you who wish to see me humbled, which I assume is literally everyone but maybe Serrinne - don't worry, I get that all of the time in arena and rateds, if I'm lucky enough to even do them. Rated's are no where near the same skill composition as randoms though.

All of which is to say, what is it with Silvershard Mines? It could be any number of things, or a combination of several. 1) Alliance sucks at SM. 2) I suck, and just got lucky in those other BGs. 2) I'm ok, but those other ones favor Alliance. 3) SM favors Horde (this is objective fact on Lava, but it's debatable how much that ultimately matters). 4) I suck at SM, and aren't as good at effecting a positive outcome. 5) The nature of SM makes it so that individual contributions are less meaningful than other BGs of its size. 6) Statistical anomaly. 7) A combination of a bunch of random and complicated shit that is really difficult to isolate and pin down.

To be honest, I'm inclined to believe that last one mostly. But I'm trying to finish up this 100 win achievement and it's really frustrating to have a noticeably lower win/loss ratio compared to other BGs. I'd be curious if this is unique to me or something others are seeing.