Let's say GF decides to allow a story based thing to happen in another region which allows for 1 town to return (assume some reason will be given for why you cant go further than that. Assume though that you can go back to it as many times as you want).

It would be updated to full 3D with SM's graphics and scale and the town will be slightly updated to signify that time has passed since last visited. The extent is based on how much updates would make sense for the town. Which old town would you wanna see in full 3D the most?

>hug city with skyscrapers and many areas
>overlooks the ocean
>probably expands over the ocean even more, being half a city on water
>plenty of underground areas
>great blend of old and new architecture

Goldenrod City would be literally perfect in full 3D