I just hope the switch to the 3DS finally does away with Event Pokémon. If there's one thing I hate about the series, it's Nintendo's obsession with on-cart DLC.
So many cool Pokémon and events that either never get distributed (we still never got the Flute to go meet Arceus and catch it in-game), or are only available for a week or two before going away.
Hopefully with the 3DS actually being able to fully support DLC and expand upon games and such, we can make event Pokémon available for more permanent download through the e-shop (and, with luck, even keep the events if we choose to reset the game).