>>43145182If you can't use mons you caught in previous regions in the next regions, then what's the point?Just play the games separately at that point. Also the more regions and gens that come out, the more all regions 1 game becomes impossible to design around. The other issue is that there is heavy redundancy between the regions with most towns just being a gym pit stop + whatever and that whatever is found in every region - it's pointless for multiple towns to have the same important NPCs around.
Sticking to something like 4 regions would be best both for feasibility and gameplay purposes. The real way to format the game, is with heavy gating of areas and bouncing around the region using cruise ships, trains, and planes, etc. So if the game is all 4 jap based regions, for example, you might start in Johto but only have access to a couple towns at first before you are forced to take the Magnet Train to Kanto, and then you repeat.
In the post game, everything opens up and you can explore anywhere at any time. However, you'd have to redesign large parts of regions to avoid redundancy. Small early game caves and forests would need to be expanded to be better for late/postgame. If you have multiple towns that area only useful for gym + breeder or beeg marts that all have the same items for sale, then most of that is pointless and need to be redesigned with other new stuff to do in those towns. Without doing this, multiple regions in one game would feel hollow and empty.