I was never opposed to the idea of a hybrid. I thought that was where Nintendo was headed eventually, just not for another generation or two. I remained skeptical because I didn't think the technology was where it needed to be to do so correctly, and the verdict is out of that one. What do you sacrifice in order to launch this in the near future? The expectation is a single device acting as the best of both worlds; the reality is a single device that's mediocre at two things.
As someone who merely tolerates handheld gaming just to play those games, a hybrids more or less works for my habits. I get to play all those games on a TV. At the same time, a shared library did the same thing. If NX ultimately ends up being only a portable that can plug into a dock with no dedicated console, I don't see that as "a brand new concept." The Razer Edge Pro was basically that. It's easy to point out that the Razer Edge Pro failed, but that's not the mark against it. I believe Nintendo could take that concept much further. However, I don't believe the concept is different enough.
I'm in the camp that thinks Nintendo has to offer something different, and if it ever hopes of taking back significant market share it eventually has to knock out either Sony or Microsoft (probably Microsoft). Nintendo can't do that by offering the same thing because there's no real reason why anyone would just drop an entire ecosystem all their friends are part of. Being the platform that ends up in more homes by virtue of second-console status is the path of least resistance. Nintendo takes back market share without taking on Sony and Microsoft. I think that was always the plan, but Nintendo just couldn't figure out how to crack it in a sustainable manner (Wii was lightning in a bottle). Nintendo doesn't care about being first. I mean, it'll take being first, but it mainly cares about profits.
What's that have to do with this latest NX rumor? Well, if the SemiAccurate rumor from May also proves true, Nvidia gave up the farm to get Nintendo's business. That means Nintendo gets better performance for a lower price which could mean higher profit margins... just not on hardware. If Nintendo is smart, it will pass those savings onto consumers in order put NX in homes with the intent to sell more software with a larger install base.
The problem is that the best portable hardware is still low-end hardware which ultimately means alienating an entire segment of the market as well as most Western third parties. This is where I think a shared library would benefit Nintendo. It wouldn't launch high-end hardware because that would price the console out of its primary audience. However, if Nintendo has a product for that audience (e.g. an NX portable-hybrid), it can finally launch an enthusiast console without fear that the software won't also sell. Yeah, the dedicated console would undoubtedly sell worse than the portable-hybrid, but that's not the point of launching it.
One or the other is not different enough. Together, Nintendo might have something.