"First of all, the next-generation MMO that we'll be working on is going to be different than Final Fantasy XI. And even though we have the same staff working on the project, and we have seen the good things from XI, and we've also seen the things that the players maybe didn't like as much...while we're going to be using that info while we make the next MMO, we're not going to make something that'll be exactly like FFXI. We're aiming for something different from the beginning."They added by saying the game won't necessarily replace FFXI and they hope that both can exist simultaneously.
"We want them to exist in the same world, to continue on side by side, without one replacing the other. And like we've always said before, as long as the players keep playing FFXI, we're going to continue making the content for it, and that has to do with the expansions as well. If players keep saying that they want to keep playing and that they want these things, then we'll keep providing them for them. For the time being it'll be handled with patches, like we have been doing. As for any announcements on the next MMO, I can't say anything."Only time will tell how big of a change this game will be, but it's nice to know they learned from FFXI and will attempt to improve on the games shortcomings.
Source: http://www.1up.com/do/newsStory?pager.offset=1&cId=3168323