First it isn't a Horde capital. It also seems like this will be the reason why the Zandalari finally join the Horde.
Second I hope to hell we destroy the shit out of that city. Sick of having to fly to the docks, should have had everything in one location like the Alliance city.
Thirdly just like SoO every time the Alliance attacks and takes a city they immediately give it back to the Horde. The Horde has destroyed several Alliance cities and at least one of their own so even if it was destroyed the Horde would still be ahead.