>>29390057New region, base it in England or Italy or South America or some shit, I don't really care. At least 100 new Pokes
The gym leader format returns with a looser approach like in gens 1 and 2, allowing for some sequence breaking of the gym order. Instead of a traditional Victory Road, you enter into a bracketed tournament (sort of like Silver Conference from the anime), and must gain a certain amount of points to proceed on to the Elite Four.
After beating the Elite Four and the Champion, you "become" the Champion in a more real sense than in previous games. Once you are the champion, you may enter the Elite Four area at any time and partake in the Champions Challenge, a sort of battle facility mode where you stand in the champions room and beat one trainer after another a la Maison for points. You can put your score on hold at any time but if you lose, you lose the champion title and cannot re-enter the Champions Challenge or use any of the perks of being Champion until you do an Elite Four rematch and take the Champion title back off of the NPC who beat you.
While you're not holding the title of champion, you may set up your own Gym, which involves you creating teams for your gym trainers and creating the layout. Afterwards, a non-stop gauntlet of trainers try to approach you, again like Maison. Your gym trainers stop some trainers from reaching you but you must face off against the ones who do.
In the post-game, you can go back to the Victory Road area to partake in various different tournaments being held with many character cameos in a manner similar to the Pokemon World Tournament.
It'd never happen, but this is what I would want. A Pokemon game with actual mechanics in place for becoming the champion, running gyms etc, and with some elements of the tournament format borrowed from how the anime portrays the leagues. The league system was never really explained very well in Pokemon, it's full of holes if you ever stop to think about how it's set up