How about instead of sequels or remakes, on the next console after 3ds, they remake all current regions on one game.
Im not looking for a massive storyline or super in depth NPC backgrounds or anything, but a fully integrated pokemon world. We have seen trains, cars, boats, even an airplane (although we couldnt use the plane). Why not let them function as the train in gold/silver, ferry between regions. Most are supposed to be Japanese region anyways, hop on a plane to X/Y region, whatever.
Since games can also be downloaded now, straight to console, imagine if they just set up a whole pokemon world.
Instead of selling a new game, sell a new region for download. Same price, whatever, but instead of being standalone, have it fill in a portion of the overall world map, with the ability to move there from older regions you have downloaded, or vice versa.