>>39897922>>39897922This
Sinnoh has memorable lakes, flower plains, swamps, foggy hills, volcanic area (much bigger than hoenn's), comfy towns with a certain aesthetic and also the resort area which gives off a different environment from the rest of the region, not to mention that it's based in a cold area, which explains all the caves and a cool vibe.
There are 2 regions that I also think had a unique aspect,
Unova that had a take on the modern era and Johto, that had a more traditional one
I don't understand the forced take on hoenns region being the best, the towns are bland and there's nothing interesting about watery routes.