IMO, hybrid - and by this I mean a powerful-ish handheld that docks with a home station, or links to the TV - is a bad idea because it forces Nintendo into having a single device that doesn't suit all markets.
It's clear that Japan is moving - has moved - handheld/mobile, and while consoles have a place, it's shrinking. In the west, consoles are still big business while handhelds have been encroached on by mobile (in Japan they seem to co-exist relatively well).
A hybrid doesn't really fit either market - it wouldn't have the grunt of a home console for the West, and it likely wouldn't be cheap enough to succeed in Japan as a handheld.
Multiple hardware forms based around a common architecture/ecosystem lets Nintendo target global markets differently, and offer platforms for different segments of each market, without having to support two totally distinct home/handheld platforms, and without mashing them all up into one Franken-platform. It comes with its own set of risks, but I see it as a better option than a single hybrid platform, or two distinct home/handheld devices as with GCN/GBA, Wii/DS, Wii U/3DS.