I am conflicted on the question of motion control and screens. In some ways, these feel like failed experiments that never caught on with developers, similar to Kinect. But, they are also ideas that could evolve well and it would be a shame to lose either of them, unless there is a new technology to replace them. That is the big question... does Nintendo have a great new innovation, or is the hybrid idea that they've been hinting at for years "it?"
The breakapart controller is a good idea. Also, remember that whole perspective shifting with head position patent, to make it seem as if we are looking through a window. That would be an answer to VR that doesn't require extra processing power or much expense.
I agree with the thinking that a hybrid will fail to work if it is just a console and portable that work together. We've had that before in a couple forms and, while interesting, it is just too much to ask from the users and the fragmented user base makes it unattractive for developers. If anything, Nintendo needs to be unifying their platforms.
That could work in a few ways, with the most obvious being a system that is essentially a portable console, apart from being able to stream video to a TV and accept Bluetooth controllers. Even most cheap cell phones can do this, and Nintendo has the proprietary lag-free streaming tech. Sitting in a cradle might add some hardware muscle, similar to the Surface Book Pro having a discrete GPU in the base. Still, I don't know if that is really worth the engineering effort if a mobile GPU is good enough for decent 1080p graphics. Developing for just one configuration would be simpler, too. Scaling down textures and turning off effects could be a quick fix, but the entire game would need to be tested in both configurations.