Shadow Pokemon?! As in Orre? It would be a good idea if Pokemon wasn't as randomspot555 said a handheld game genre. After all It started as a hand game and it most sure will remain true to it's origin.
Although multiple abilities does sound right to a certain point.
Also... Magma and Aqua disbanded after the Hoenn indecent.
BTW: Elite four from every region would not make them four. And if you count the Champions that rules their regions they add more to the E4 since there could only be 1 Champion.