I think the servers should be balanced for free, I don't see why the population should have to pay for this service.
They should look at the lowest population servers and close them giving all players free transfer to another server.
Im sure they could close a fair amout of servers which will save on running costs.
Get players to pick which servers they want to move to and keep track of who is moving and try and get the population more balanced for the players who want to play and want to have a more active community on the servers.
I really don't see why there is so much stigma with closing/merging servers, If a company believes they will have a 100% retention and not put plans in place for rebalancing the population after the inital drop off then they are living in a dreamworld.
And after the redistribution of the population then the cost of transfers should be done via in game credits not RLM.