>Kanto
Everything feels grimey and industrialized, which helped the games dangerous atmosphere
>Johto
Very nice balance of locations, you get a strong sense of lore, mystery, and culture
>Hoenn
I like to consider Hoenn as Adventure Region A. While it DOES suffer from too much water (Fuck those last 3 routes in particular), its a very adventurous Region showcasing tropical environments well, even better in OR/AS
>Sinnoh
Adventure Region B, this time showcasing the more comfier wintery locations. Mountains, lakes, and blizzards await, and the comfiest towns with the comfiest music in all of Pokémon to make up for the long struggles.
>Unova
Sadly bland Region. A few cool locations, such as Virbank in B2/W2, made for some nice pit stops, but most of the Region just has you rushing from one route to the next. HOWEVER, it makes up for this in character and lore, and to date, no Region has ever felt so full of life. It also has hands down the best desert area of any Region so far. Exploring those tombs was amazing, and the Pokémon there were very fitting.
>Kalos
Visually stunning, probably the most beautiful Region to date, but suffers from the fact that due to the Region being a circle, it felt like you were moving through the seasons, each to small to give you any sense of exploration. The wintery snowy area for example felt like it should have been the ENTRANCE to a much grander adventure.
Conclusion:
Johto is my favorite Region due to the balance of mystery, culture, adventure, and comfiness. Sinnoh is second due to its adventurousness, and Hoenn close behind, losing a few points because after a while, surfing doesn't feel adventurous at all.
Kanto, Kalos, and Unova all trail behind. Theyre by no means bad. Each of them has a lot to offer, I enjoyed all of them dearly, but they dont have the same adventure and wonder as the other three.
/opinions