As an Australian who's frequented WvW for many years and played on GoM, AR, SoS, and FA - I can confidently say that there is a stacking problem. SoS has the largest oce pop by far and when they match up with the likes of AR they just run around in a circle capping everything and chasing the 3 opposing players they see across the map. You might call that engaging gameplay, and you might also be an idiot.
Here's hoping the Alliance system resolves some of these issues, because I don't really want to pick between fighting a blob on my own, or fighting a door with 30 friends.