They could also do it like the FFIII/IV DS remakes if they wanted with better models since they would have more horsepower, it would probably look like the Trials of Mana remake. Or they could also do it like the VII Remake and incorporate Yoshitaka Amano's artwork into the world design, like they did for the PS1 intro/endings. Honestly they have a lot of options on what they could do. My only rule is that if they are going to bother remaking the game in 3D then actually go all in and redesign the world and dungeons to work in a 3D setting. I don't want a Secret of Mana style remake where they just give the game a graphical facelift but keep everything the same.