What defines the best pokemon region?

I wanted to know what would the best region in main pokemon games for you which you would to love to explore all over!
Mine would be the one with
- More than 8 gyms
- Various landscapes like plateau, deserts and caves
- Both snowfall and rainfall
- Abundance of pokemon

I personally am a Hoenn lover. I just really love the tropical environment, and I love all of the water and all the time I spend surfing through it. Plus all of the environments are very bright and vibrant.
I don't care that we just had Hoenn in generation 6, I would still love to return there in the future again.

If I wanted some improvements to the region, I think most of what I would want would be taken from other regions. I would love for there to be seasons as there were in generation 5. I would want the resort island to be expanded more. I would also like to see weather changes that provide a variety of weather conditions to certain routes and towns as well as having season appropriate weather. I also think it would be really interesting if there were festivals or holidays, like maybe NPC's would be in the streets celebrating certain holidays or festivities. I think it would be more interesting to see environments change after major events, for example after Kyogre causes the torrential downpour, it would be neat to see certain maps become flooded and such.

I feel like I'm asking for a huge sandbox remake of Hoenn, but hey, dare to dream.

A game without any road blocks would be ideal. Playing through Black and White right now, and it's almost perfect. The towns are interesting to look through, there's a variety of Pokemon in different routes, but my only issue is not being able to progress somewhere too early.

I know most games will create some sort of block, but it would be cool to see it like a non-linear older RPG. Let me go into the wrong area and get beaten by level 30's. Kanto actually did this, letting you get the Tea/Lemonade, you were able to go into the fighting "gym" way early.

There's no perfect region in the games but a bunch of times they've introduced regions that contain one particular aspect of an amazing region design. What if you could combine an amazing setting and creative town designs (Hoenn), an extensive and well-written backstory (Sinnoh), and a large and mostly unbounded map with a ton of side areas and optional exploration (Unova). That'd be pretty close to perfect to me.

Unova. Beautiful region. Good amount of post game areas. Able to catch fully evolved pokemon like Tyranitar and Metagross in the wild. Perfect story through both pairs of games.