I've noticed a steep decline in the Horde population recently. To the point I'm having difficulty selling normally quick-cash items(frozen orbs, gems, etc). Perhaps a way to make the server feel more full for Horde players would be to link Alliance and Horde auction houses? Maybe even low-level dungeons? Four hours for a WC is a little long XD
I don't think it would detract from the sense of community(If anything it might make it feel a little more communial?), and if would definitely add some interest for remaining Horde and boost Horde morale. Which would only benefit Alliance PVPers. I'll admit, I'm sure an empty WG is boring for you guys!