They were segregated because of the economical impact that 1.0 players could have on a new server. Even though our gil was slashed by 90%, people that had a lot of money still have a lot of money since prices from vendors were adjusted in accordance with ours, so the value of gil didn't change.

If you want to continue playing your 1.0 char your friends can always join you on your Legacy server. From the looks of things, it doesn't seem like any of the ones from the NA/EU region will be filling up before the transfer period ends.