I think cross server linkshells or anything like that would be super hard to implement if they didn't plan for it already. It may happen in the future, and it's nice to dream about while eating your delicious oatmeal cookies, but it'll be faaaaaar into the future, if it happens at all.

For me, I really have to decide if I want to stay with my LS should they choose to stay on a JP server and if I want to deal with the 200 ms lag. I really like my LS but the lag, for me, made the game almost unplayable at the level of playing I wanted to be at. Killing random mobs and easy endgame was doable... but... Being the solo healer in Ifrit Extreme put a lot of pressure on me. I couldn't mess up. I couldn't get hit by things and die... but when you hit a lag spike with 200 ms lag default, it's going to happen. Weirdly enough, I had the worst problems with lag late at night. o.O;; Some people have gotten upset when I've said that I need to be on an NA server (no matter what), but if I choose to stay on a JP server, I'll be useless at hardmode endgame and then I won't even be able to participate in the most recent content without the lag killing me.