No idea, but we can always hope... :confused:
It would be very interesting if some pkmn got new forms. New functions are always fun too, everything new is fun I think... =P
I also hope there will more quests for certain things, like The Lucky Egg Quest in Pokémon : Gale of Darkness. That quest was really nice.
It would also be a bit fun if they up-graded the way you FLY to certain places, it would be cool if you had the option to see how your pkmn actually flies you to the chosen location, over houses, trees, water, other stuff... But it must of course be an option to turn it off and fly the old fashion way.