It would be a good idea to only allow new players onto the current servers via an invite from players already on them said servers,

In other words if you wanted to play on moogle you can only do it via a invitation from one of your guildies or a friend that has already been playing on that server.

this would stop players from just going to the most full servers. which is bound to happen it always does.

So dont allow players to just create a char on a server that is already full, except for players that need to link up with their free company or friends.