an XI remake was in the works up until a few years ago actually, so SE obviously sees it as a worthwhile endeavor, but after Nexon folded up on the project they might be gun-shy about trying again any time soon.
I think all they would need to do to revitalize interest is combine the launcher and give a discounted sub with XIV.
As for 1.x content getting revisited... how about To Kill A Raven (Ultimate) or even (Unreal)? (and no, Coils is not the same thing just because it features a version of Nael)