Sinnoh as well.
Routes are wide, dungeons are complex, there are optional areas to explore, and the entire region loops back on itself with Mt. Coronet serving as a landmark REALLY well.
It feels like the one region that seriously focused on exploration, for Pokemon standards.
It's the one region I want to see in 3D, true 3D with free camera would look amazing with all the verticality that comes with the dense mountanous areas it has. But I know they'll fuck it up and make it all blocky like ORAS instead of fleshing it out properly.