Nobody appreciates Rotom anymore... despite you could get him through trade by trading a Ditto with the girl in the trailer by the PokeTransfer place. Also, in this game, you could change his form without the event, unlike Platinum. You can do this in the Outlet 9 mall, on Route 9 (of course). I believe that Heatran is also extremely forgotten, too. He only appeared as a slave pokemon in Pokemon and Arceus: The Jewel of Life (i believe).