Pokemon Crater, right?
I would love to see variation of Pokemon such as Light, Dark, Metallic, etc.
They could be very nice for collection purposes. I know I would take time out of my schedule to hunt for them.
Alternate colored Pokemon such as the purple Kecleon that appears in the anime/PMD games would be a very fun aspect of the game.
I don't think that'll actually be present in the game but hey, anything can happen.