If they want people to move off of the big servers they will need to address the main reasons people want to go there. Why does large population still matter?

Hunts
Economy
Friends

Need cross server friends lists and ignore lists, with the ability to group in open world and be in the group leaders server zones.
Need data center wide market boards to balance the economies together
Need an answer to hunts to prevent the use of above ideas for some form of abuse
Need a couple servers specifically labeled for RP. Not just Balmung unofficially but actual rp labeled servers to draw in that crowd.