That won't be an issue though, a few servers merged, will mean each realm will have a few big alliances, for example merge 3 servers and each realm will have at least 3 big guilds.
Yes some players will move, but a lot will want to compete in the guild they move over and try and be number 1 on the new server. Which should in theory mean no guild will control all the cities, so more than one guild in each realm will get benefits.



