I really don't think they they would just disregard FFXI, considering all of the effort that they have put into it and with all the new styuff that they ae introducing like Chocbo Breeding and ToA.

Personally I hope they make it so that it is a sequel but you can carry your characters over and basically they improve the graphics majorly as they dont have to worry about the PS2 and introduce loads of new stuff, maybe even set the game in a whole new world.