The sad thing is that I could actually see a sequel to Vagrant Story working, assuming the original team got together to do it. I always imagined a sequel would deal with a new protagonist who had to hunt down an older Ashley, whom would play a role similar to this new character that Sydney did for him. Course I feel seeing the team come back and do a remaster would be pretty snazzy as well.

I doubt Einhander would get a sequel, but that could possibly change since I read somewhere that the team who worked on it are working on the Gummi Ship sequences in KHIII, so who knows.

For my own takes, I feel most of the FF series doesn't lend themselves well to sequels, but special mention would go to FFVI which I can't fathom how a sequel story could even work without coming up with some BS plot excuse. Maybe a smaller more intimate "where are they now" snime/manga adaption, but nothing on the scale of the sequels we've seen of other FFs.