Well since nobody answered to this question: I think they ALL should be completely re-made from the scratch.

There is nothing to explore and nothing Final Fantasy-like about them. What I mean is that there is nothing memorable about grassy hills a desert and a forest. These locations could easily be in any very generic game in any genre.

A trip from Windurst to Jeuno has shallow rivers in the grassy fields of Sarutabaruta with Horutoto ruins and odd trees that leads into the Tahorongi Canyon that has a haunting atmosphere and a massive Tele structure in the middle of snaking tunnels. There you can go to another massive zone with a jaw dropping skeletal structure built over it and a dungeon with Yagudo architecture in the north. That scenery changes into a war-torn battlefield with beautiful music and scars of war seen everywhere including holes that tell where the bombs fell.

In stark contrast a trip from Gridania to Ul'dah features a forest and a desert.

Doesn't quite compare now does it?