While it's nowhere near as absurd as, say, Pokémon Box on the GameCube, ONM are struggling to see the point of My Pokémon Ranch.
So, you transfer your Pokémon from your DS copy of Pokémon Diamond and/or Pearl... and that's it? It seems so. True, you can watch your Pokémon interact and have your Miis wander among them, plus it's nice that the game seems to be a motivator for helping you find Pokémon you haven't got in the DS games as you are given tips for finding them.
