The CPU is a design from 1999 and WAY past it's life expectancy, and newer IBM processors are wholefully inadequate to the needs of a videogames console as they are designed specifically for giant High Power Servers, which consume electricity by Megawatts. That's why a change in CPU hardware is basically a must and thus backwards compability out of question, unless they include a shrinked Wii U processor & graphics just for this. But that would again increase it's costs by at least 30-50$.

Besides, I think NX will be a sucessor to the 3DS, not the Wii U, so the article is probably wrong in any case.

It will succeed both. 

I have a dream that Nintendo will launch a Netflix-style subscription service for their future systems.
Imagine if it has a Nintendo Land like presentation and contains every past Nintendo-published game that they still own the rights to. Different portals leading to different consoles and have it all drenched in fan-service.
Not gonna happen though!

Couldn't Nintendo just make it digital backwards compatibility, like the PS Vita with the PSP? I think the NX will be the Fusion, and it will be able to play digitally games from every Nintendo console.

The problem here is the WiiU. Not only you would need to pack some special hardware to make the NX backwards compatible wih the U (I'm sure that, at this point, emulating the Wii and GCube won't be a problem for NX hardware), you'd have to adapt the games so they don't recquire the Gamepad if they decide to sell WiiU games on the NX eShop.

Would be odd if the NX couldnt play 3DS and DS games

I'd like it to be backwards compatible, but it just may not be possible. It's more important to me that it has adequate third party support, and that will take modernized architecture.

I've said I don't think it'll be backwards compatible because of how Nintendo operates. As bad as the Wii U has sold, Nintendo will make a comment how there just aren't enough games to justify backwards compatibility. However what they'll really mean is, "fuckers aren't supporting us? Damn if we'll let them have access to SSB4 and Xenoblade by offering BC."

Does anyone honestly think that a large portion of Wii owners went back and played gamecube games, or even cared to acknowledge gamecube games? It'll be the exact same situation with NX (home console).

Nintendo will likely drop BC simply because it doesn't make any sense going forward. The Wii U was not successful so Nintendo have no interest in trying to carry along its audience as they tried with the wii audience and unlike gamecube/Wii, NX architecture will likely be very different from Wii U. Logistics has been the only thing behind past BC as far as Nintendo's home consoles are concerned, that is now (probably) out of the window.

I think Nintendo will just port their most important games from SNES-Wii U on NX (both handheld+home console) and give them digital releases. One or 2 wii U games may see retail remasters instead (Xenoblade, Zelda?)

Why wouldn't they drop it? Sony has been making a lot of $$$ by just porting games to other consoles, if there's something that catches companies' attention, it's easy money, plus, if Ninty it's supposed to be relevant again next gen and get more people into Ninty things, it would make sense to port games that only hardcore Nintendo fans have played (AKA every Wii U game) to a console with a far bigger userbase (let's hope).

Fair enough but if there is no direct replacement for wii u as a home console then clearly it will be an exit strategy especially if its clear the handheld side dominates sales.