I'm actually happy to hear the there won't be a choice in server transfer. This way, the entire community of a server will be moving to another one, not being fractured to multiple locations.
1) Ensure that all guild members will move to the same location (although not the most ideal way to transfer a guild)
2) Ensure that guilds with rivalries will be moving to the same server
3) Ensure the friends you've made in game will be on the same server
I just hope that the 60 active people on my server and I get the chance to move