It is really really simple.
Allow free character transfers between oceanic servers. Guilds and players can then choose what to do, you will quickly see a re-balance in population shift as people chose the best server for themselves. After a few months you might find that 1 server out of the 3 has almost 0 population and you can then look at decomissioning it. This will save you money in operational expenses in the long term and will give us the chance to choose where to go for ourselves.
It is a no brainer seriously
That could get messy, with people jumping all over the place and getting confused. Personally I'd prefer a simple merge.