I personally love Final Fantasy XII citing it as my personal second to Final Fantasy VI. So a sequel in my book is all to late, but still welcome to sleep in my bed while i take the guest room.
This is all speculation at this point, but it's being followed by a twitter page, which some claim as official, but it's really too bland to actually tell as of yet.
The synopsis has a few interesting bits of information. The biggest being the city of Leá Monde which hasn't been seen nor heard of since Vagrant Story. You can almost tell that the influence of religion and religious affairs will most likely be more apparent then in previous Ivalice based tales. Since I assume it's not an actual staple to core "Final Fantasy" it's gameplay is a complete mystery as it could inherit Final Fantasy XII's MMO style gameplay, with new an improved mechanics.
This also reminds me of a title I was hopeful for a while back. it was dubbed "Fortress" and sounds awfully similar. Except that it was said development fell through and it most likely will never see the light of day. So whether this is the same title or not has yet to be confirmed.