I don't understand why MMO's even have separate servers/shards in the first place. They have the technology to balance the load across all the physical servers and allow everyone to interact, similar to GW/GW2 and EVE. If I'm on Belsavis, for example, I should be able to interact with anyone who is on that planet....no matter what server they're on. Every 100 people could create another instance of the planet and you could just switch to that instance if you want to group with your friends.
The fact that BW didn't have the foresight to realize this means they most likely can't implement this in the future. It's really sad that they are segregating their player population, it's mind-boggling.