Anything short of a MASSIVE 3DS game is absolutely unacceptable. I expect MAJOR updates to the formula, all new areas PLUS the possibility of revisiting at least one older region, a story with some actual drama to it instead of the usual 'collect 8 badges and save the world on the side' bollocks, decent length, new pokemon that had some real effort put into the design process PLUS the ability to catch all previous pokemon, including all legendaries and 'mythical' pokemon like Mew, a HUGE improvement to the graphics 'cause they're getting pretty bloody old, the pokemon make noises OTHER than those crappy cries from back on the original Gameboy because they have NOT aged well, and perhaps even some sort of multiplayer campaign if there's time to work it in.
This of course will never happen, and if it did, we would take it as one of the signs of the Apocalypse. BUT I CAN DREAM, DAMN IT!