Well, I started the paragraph explaining that it's a matter of opinion, but I'll explain why I think the way I do.
I've played every Pokemon game and none of them felt as real to me as the originals. It could have been my age and imagination responding to the limited technology, something fueled by the anime series that I watched as I played. Kanto feels like a real place where real characters lived and the others never did that for me. Charm doesn't have to come from a giant empty city with a tower in the middle or another set of enormous world-ending legendary Pokemon to stop. It can come from being on an adventure when you're ten years old, traveling through caves, fighting trainers on cruise ships, and learning how to navigate the world while trying to be as strong as your rival. Pokemon lost a lot of that realness as I got older. The original games were built on hardware scrapped together in 1989 out of already outdated tech. It has an excuse that new games don't have.
Pokemon never stopped to flesh out the world that these characters lived in. The GameBoy literally couldn't do it so the anime and the N64 games were there to help us visualize what this world was supposed to look like. As things progressed we never saw more of what a Pokemon Breeder did day-to-day. We never saw what a school is like in the world of Pokemon, at least no more than was relevant to us as a Pokemon Trainer. Landmarks don't mean much to me. It's all about the people, and the people in Pokemon games are just as robotic now as they were before we had color in our portable games. Again, it's a matter of opinion. Most people can look past characters with no idle animations who sit there with no role to play, doing nothing until you talk to them but I personally can't. Sun and Moon made pretty big strides in making the world feel more interactive and alive but a console game needs to do much more. That's what I'm hoping this new set will do, and It's my opinion that the setting is Kanto to best illustrate this.
Or I could be wrong, nothing will have changed, and revisiting Kanto will be a complete waste of time and we'll all completely agree with the concept being a poor choice. Even if that's the case people will have about six months to be choked up about it before another bloody Pokemon game is announced and hopefully that one will have the region people would rather see.