I'd like to see a good FFVI remake on NDS, just like FFIII or IV.
Of course FFVI is a GREAT game itself, and even its graphics is somehow touching and iconographically perfect; but I surely would cry if I knew a remake is going to be released.
I think there's nothing to change in the plot, anyway: I especially love the WoR, which is the true masterpiece within the masterpiece IMO. You're free to do almost wathever you want, and you can appreciate how your characters are psycologically grown (Terra *_*, Locke *__*, Cyan *___*, Celes *____*...).
I love FFVI as it is, but it would be pure apotheosis to see a 3d Kefka.