Less than a year to port is a lot of time, not sure where that idea comes from, if you needed a year to port multi-plat games releasing day and date with each other would be a miracle. 

Zelda was downgraded from the original version too. I don't think Switch or Wii U are capable of actually running this without large frame rate choking:

There's a lot of detail going on there that would cause both of those systems to choke. So EAD's vision already eclipses what is possible with a Tegra X1. 

It is a lot when you have a complete game. But that was not the case of BotW.

That was a concept. Death Mountain, Hyrule Castle and Guardians are different. Aonuma and co already confirmed that not even the ancestral arrows were originally planned to be included, but after the positive reaction they decided to add.

I'm not talking about the placement of things, I'm talking about the actual graphical detail. Wii U or Switch wouldn't be able to run that, that's borderline XB1/PS4. 

The game that we got is pretty nice of course, but it's definitely not as detailed and fluid as what you see here. 

Yes I know. I always said that. Yet, that does not confirm that poor optimization of the game on Switch has to do with hardware when there are other games that runs well.

Splatoon 2 only being 720p is also another can of worms. Racing games are just less demanding because there are very linear by nature. 

Game is still not finished. If by release date it is still 720p then I will agree.

I honestly don't see a resolution bump happening in 2 months time, it's not something you magically snap your fingers and your game engine is suddenly drawing 2x as many pixels as before. 

I think part and parcel why Nintendo chose a completely non-custom Tegra X1 as well is precisely because they intend to replace the X1 chip over time. 

If they were going to use that chip for 5 years, they would have probably opted for a more custom design. I would bet Nintendo's designers are not happy with the lack of any kind of eDRAM/large RAM cache and only 25GB/sec memory bandwidth. They love their embedded RAM, even the 3DS chip has some. 

The memory bandwidth is likely what's causing the Zelda slow downs ... it's likely just not able to handle such a huge environment at a 900p resolution. I think that's where the bottleneck is, not lazy programming. 

The trade off of not going custom is that you can swap out chips for future Nvidia iterations very easily, so likely one faction of Nintendo's design staff won out over another one. 

From what we've seen as well it doesn't look like ARMS runs at 1080p either, that's 900p as well. Mario Kart may well be the exception, not the rule. 

Basically what BoffferBraurer said; you're making a lot of assumptions here and we know very little details about the SoC itself. I wouldn't jump the gun that fast, especially expecting revisions for some time.

As far as I can see, Nintendo designed the system to be as universal as possible in terms of the form factor. If they really need extra horsepower they can raise the clocks a bit, the Joy - Con are very modular and sized well enough for most hands, so is the system at a size which is just portable and light enough. Making a docked - only or handheld - only Switch also goes against the entire name and marketing, and they probably don't want to cause any confusion in terms of what the system can do. All in all sticking to the same system for a while is their best bet and also allows them to eventually drop the price by a bit or start bundling in games.

Also, it wouldn't be called the X3 since it isn't MaXwell based.

Unrelated - Xaiver - like SoCs running at full capacity would provide very good performance while being cheaper, smaller and consume less power than an adequate CPU + GPU combo. With Microsoft working on Windows 10 for ARM platforms, modular ARM PCs could prove interesting. A casual web browsing / light gaming machine built with phone components could easily cost around $50 with a MTK / Rockchip SoC and 8GB LPDDR4 / LPDDR3 RAM, and more powerful machines could prove capable for gaming.

The 8GiB RAM alone would cost around 50$ at least right now. RAM prices are rising up again since last summer due to lack of production capacity, and many PC DIMMs have already more than doubled in price since then.