WSR and NSMB are problem games so it is not your wii is at fault.
With WSR you need to play a dol file first using neogamma, this enables you to watch the demo of the wii motion plus in use. Once you ahve watched this demo in full and switched the dol file off WSR will work.
Regarding NSMB there are copies floating around that work. And most will work with usb loading.