Or, to simplify the whole thing, just have a difficulty setting option in the options menu...
I feel like Black 2 and White 2 may have been a test to see how difficulty settings in Pokemon were going to be received. By making them unlockable, but not present from the start, Game Freak could see what people were mainly going to use and go for based on feedback (not direct feedback, more like investigating online to see what people are talking about).
I know almost everyone wanted the "Hard" difficulty, while most people didn't care about the "Easy" difficulty. So, if Game Freak has been listening to us even a little bit, they'll probably put the difficulty settings in the menu when you first start up your game, as it could lead to a completely different feel for this generation if you started out at a disadvantage/advantage compared to previous generations.