finally someone agrees i think i will soon make a thread about it..

The only problem with this theory is that they can't wait that long. There is no way to extend the life of the Wii U beyond 2016. Nintendo hasn't even hinted at any more major Wii U projects being in the works past Zelda U, and otherwise Wii U sales are not going to magically become passable for Nintendo. They need to leave the Wii U and everything "Wii" behind them, and unfortunately that's probably going to mean launching in the middle of the current generation. Nintendo has set themselves offbeat here, and I don't quite know how they're going to make things work when the rest of the game industry is operating on a different schedule than them. They can't really divorce themselves any further from the rest of the industry if they want to remain successful, but it seems impossible to postpone releasing new hardware until an opportune time unless they enjoy losing customers by letting the Wii U be dead with no word of any successor for potentially years.

There was ambiguity about what form the NX would take from the start.

Iwata called NX a "dedicated game platform with a brand new concept". On the same page, there is a slide describing the NX as a "dedicated game system". Both can be seen here http://www.nintendo.co.jp/corporate/release/en/2015/150317/03.html

To me, that suggests a likelihood that it will be hardware of some sort, and that it will run alongside Wii U and 3DS under the new membership service, at least for the short term.

I agree completely. Nintendo announced the Wii U in 2011, but it only released in 2012, nearly 1 and half years later. So I think it will be the same thing for the NX.

Yes, this is direct Iwata quote on this:
'As proof that Nintendo maintains strong enthusiasm for the dedicated game system business, let me confirm that Nintendo is currently developing a dedicated game platform with a brand-new concept under the development codename “NX.” It is too early to elaborate on the details of this project, but we hope to share more information with you next year.'

This could mean a home console, a portable console, a mix of both (rumoured 'fusion') or smth completely different (phone/tablet/android device etc). 

I dont see why there needs to be a console in the first place even if Wii U is dead and sure they can make games for it people will buy it same way they do now. also they have a handheld in the works they can still make money. releasing a console mid gen would complicate things and in no way would make third parties board ship unless nintendo pays for it and they dont do that.

 Its not only me who told you your position is not correct from logic point of view. There's no insults here, just stating facts.

Yeah, none of that is true. Iwata called the NX a system, not a platform, so that kills it there.

See, the flaw in your logic is that you're making assumptions based on incomplete and vague information, using articles that aren't even proof, but rather more assumptions. In your mind though, this theory is so concrete that unless somebody can give hard evidence to refute your theoretical evidence, it won't be good enough.

You ignored the fact that announcing something publicly doesn't mean it would even be reported. I mean, what site would report "the next home console is in development"? As I previously stated, most gamers see that as common sense, and no journalist would see that as news worthy unless there was actually information about said new home console to report. You just want to be right so badly, you are latching onto anything that could possibly prove your point and bathing in a pool of logical fallacies for the sake of being right in something nobody is trying to be right in. It's theories. Theories. Nobody is stating their theory as fact except for you, which is why we keep responding to you stating how your "fact" is just another theory.

You act like evidence is necessary to dismantle strung together assumptions. It's gone from "Metroid Prime 4 would probably be on Nintendo's next console, assumed to be the NX" to, Metroid Prime 4 is coming to the NX. It's gone from "we've mentioned the next home console was in development" to "omg nobody reported on that particular moment so it has to have been about the NX". I'm not going to go digging up counter evidence for a theory. Especially when there is literally no evidence for anything yet. What you call "evidence" feels more like a poorly made joke. I don't get how it's difficult to understand that I'm dismissing your evidence based on the lack of logic behind your basic ideas that this evidence is meant to support.

Anyways, I'm done with this, and by this I mean you. This is just going in circles anyways.