FFXI doesn't need anything but content here and there. It's 10 years old.
FFXIV needs foundation work and content.
Which of the two needs more attention?
Chocies....Choices....
Pretty sure there's not enough players for XI nor development cost to justify a release of real expansion packs.
Remember, EQ is old but their new expansion packs are basically the sizes of DLC type content, which is what FFXI is technically moved into. Your fellow gamers have proven they want the DLC type system for all games or else they wouldn't have been buying DLC developers released.