My favorite part of Gen 1 is how open it is. After beating the first gym, you're able to do whatever gym you want. Progression is not locked by gyms until you need to do the 8th gym. While it may not be advisable to do gyms completely out of order, you can, and it makes Kanto feel much more open that it actually is. In the 2 playthroughs of FireRed I did as a kid and as of a few months ago, I accidentally missed the Saffron gym because I had to go out of my way to go there, which just blew my mind. "Oh cool I've been doing the gyms out of order that's so cool!" I hope this new game recaptures that feeling. I just hope the story of Gen 9 doesn't get in the way of me being able to do whatever I want with the gyms.