Issue would be RMT if you can trade then they can sell gil at any server they want without having so many RMT on each World. I don't like the idea of opening it up from servers to server it would happen like in WoW where everyone sit in city and wait for people from other world to do dungeon,pvp and such.

Best you can do is reroll which you can get all the level you have within a few days or 2week if your casaul. Or wait for the ps3 reason when all the severs would by flood by ps3 players.