Well admittedly, if Sony and Microsoft had gotten the drop on Nintendo with motion controls they would've been fucked. The whole reason the Wii sold so well so fast was because motion controls were new and exciting. Then, eventually Microsoft and Sony caught up and implemented motion controls into their systems as well.
If Nintendo does have a cool new idea I can understand why they'd want to be secretive with it until they're ready to build up the NX's release.