The other problem you run into with a 3DS XL sized handheld is there's only a certain amount of power you can put in there realistically and actually fit a battery inside that could power it for more than 2 hours. 

So if that's part 1 of your "unified ecosystem" and like every other Nintendo handheld, this is the SKU that sells the most ... you kind of have a problem with the console. 

A 300 GFLOP portable and a 2 TFLOP console or something like that the gap is too ridiculous that it negates a lot of the points of a unifed platform because the gap is simply far too large to allow for easy porting in quite a few cases. 

I think having something in between those two extremes makes sense, a more upmarket portable console. That way the small pocket NX can serve the kids market kinda like the 2DS is trying to do right now. Otherwise I think Nintendo is likely going to have to neuter the console and hold back its power, because it they won't want it so far ahead of the portable. 

But here's the thing too -- this obsessive adherence to following traditional market "rules" (ie: there must be a handheld, but it must look like a DS/3DS, there must be a shoe-box sized console for the TV and that's all) is a poisonous line of thinking for designers IMO. You'll never get anything new or really anything interesting if that's all you allow into the conversation. 

"Wait, this is a little different" is not a bad thing. Nintendo should go towards that, not neccessarily run away from it. Keep the good ideas, be pramagtic about it, but don't fear change. If they keep doing what they are doing now in the hardware business, IMO they won't be making hardware in 5-6 years time and iPhone games will be their primary business driver, so I mean shit, if there was ever a time to take a few risks ... 

Battery capacity and hardware architecture are much improved from period when 3DS was project and introduced. 3DS XL has battery 1700 mAh and pretty weak hardware specs, today phones have battery capacity 3000-4000 mAh, 5-6" displays with 1440p resolution, 4GB Ram, 8-core CPUs and suitable GPU and yet battery can survive at least 5 hours of constant using.

I dont see problem if handheld continue to sell better like it was always, that wasn't problem previous gens for Nintendo.

In case of devices (handheld and home console) I did not mentioned any specs but I dont see problem there either because they will use exactly same architecture, I don't think it would so much difference in power between handheld and home console, with handheld Nintendo will probably aim for 480-720p resolution and with home console probably 1080p with better textures and effects.

It's funny how history can repeat itself isn't it?

However "What if NX is portable too?" then damn, N3DS owners got so burned if they upgraded from a regular 3DS.

Well there is this quote from Iwata last year that Soundwave just posted,

"Still, I am not sure if the form factor (the size and configuration of the hardware) will be integrated. In contrast, the number of form factors might increase. Currently, we can only provide two form factors because if we had three or four different architectures, we would face serious shortages of software on every platform. To cite a specific case, Apple is able to release smart devices with various form factors one after another because there is one way of programming adopted by all platforms. Apple has a common platform called iOS. Another example is Android. Though there are various models, Android does not face software shortages because there is one common way of programming on the Android platform that works with various models. 

The point is, Nintendo platforms should be like those two examples. Whether we will ultimately need just one device will be determined by what consumers demand in the future, and that is not something we know at the moment. However, we are hoping to change and correct the situation in which we develop games for different platforms individually and sometimes disappoint consumers with game shortages as we attempt to move from one platform to another, and we believe that we will be able to deliver tangible results in the future."

He doesn't rule out the idea of a single device but he seems to be leaning toward the idea of multiple form factors. Also the recent patents that released were for a home console.

I've always thought that console games could have the same features as pc games, adjustable settings. I like your ideas, I would love for nintendo to do this. I think nintendo is going to do some form of your ideas, maybe not exactly like them of course, but something like it. A portable that runs the console games at lower settings.... I love the idea, and I pray that's what they're doing.

Why woudl n3Ds owners would get burned? those who bought n3Ds would probably wait for a year or two before going buying NX portable.  that is the same case across all later adopters of a console. Like buying a PS3 a year before PS4.

I've kinda thought about this, the thing is batteries are not particularily expensive. For example the battery in an iPhone 6 Plus costs Apple like $5.50. So that's no the issue per se. 

The issue is more about size. The battery is huge once you start getting into power consumption at a sustained 4-5 watts/hour for gamplay. The iPhone 6 Plus for example has 11.1 watts per hour in that 2915 mAh battery. That means at a 4-5 watt push from a gaming handheld, the battery would be dead in about 2 hours. 

You need a battery more akin to what's in the iPad and other tablets (much larger). The fourth gen iPad for example had an insane 43 watts per hour battery (I suspect the new iPad Pro is about the same or even bigger). 

Not to mention the heat being generated. 

For the portable Nintendo may honestly be better off going with a more tablet like form factor (like the iPad mini) and then waiting for a die shrink to 10nm for a more classic GBA SP/DS styled handheld as the years go on. 

Looking at the latest AMD Mobile processors a 35 watt Carrizo can pack 4 Excavator CPU cores and 8 Compute Units, that puts it in the ballpark of a Wii U in terms of power consumption, but somewhere between the 2-3X Wii U in terms of hardware performance on the GPU side, the CPU is substantially more capable than the 3 core PowerPC, in fact it would probably far outstrip the CPU performance of XB1.

That's a 28nm processor, Nintendo may have access to a 14nm Zen CPU (probably the latest GCN tech for GPU at that processing node), which will feature Simultaneous Multi-Threading, with new architecture overall and a more efficient node that 14nm tech could reach PS4 levels of performance at 35 watts, it just depends on what AMD has available when Nintendo wants to begin production.

I think AMD were hotly rumored to be producing a SOC for one console manufacturer, which would be introduced (which could mean revealed to the public or released to market or both) next year.
Nintendo seems the most likely company to be AMD's partner and this tech is what AMD has available.

Carrizo and a 28nm node would be the most mature, more efficient than the tech in PS4 and XB1, giving Nintendo choice and probably a cheaper cost, but Zen and the next line of tech that comes along with would offer a substantially bigger leap in performance, but costs would be higher, although going with a newer line of technology does let Nintendo futureproof themselves a bit.
Both options could run with a newly designed, unified API and OS, future AMD tech would allow backwards compatibility with previous generations when and if Nintendo wants to introduce the next evolution of their NX platform.

TBH either Zen of Excavator would be a good option for it's own reasons, it all depends on Nintendo's design options.
The GPU tech in Carrizo is updated, with a richer feature set, the CPU tech substantially better per core compared to PS4 and XB1, 4 cores may outstrip XB1, the GPU would be a fair bit weaker though with 8 compute units, Nintendo could always use a design packing the tech of 2 Carrizo APUs onto one die, 8 Excavator Cores (remember Excavator cores are much more capable than Jaguar) and 1.6TFlops would probably equal or exceed PS4 in performance, at 70 watts power consumption for the SOC, that's an efficiency gain of more than 30%.

It all depends on what Nintendo wants NX to be.

I dont see how exactly 3000 mAh battery could last only 2 hours in gaming handheld when 1700 mAh battery last around 4-5 hours in 3DS XL or 1500 mAh Wii U gamepad battery last around 4 hours on 6.2" display!?

About size and form factor, do you realise that 5" phones now have battery with 4000 mAh!? So we have device that is much smaller than 3DS XL (not mentioned Wii U gamepad) with battery twice of Wii U gamepad capacity.

Smartphones generally are not pushed to 5-6 watts/hour, things like browsing the internet or what people normally do on their phone eats up maybe 2-3 watts/hour. 

You want a battery more like the one in the iPad Air 2 -- 7000-8000+ mAh, then you can get a fairly high end level of gaming performance (PS3+/Wii U level) using a 14nm chip at 70 GFLOPS/watt. Or even better yet the monstrous 11,560 MaH battery from the 4th gen iPad. 

The battery isn't even that expensive, it's just that it's large. It would be very difficult to put that kind of battery into a 3DS XL form factor for now (maybe when you get to 10nm that becomes a possibility). But it would be workable in a tablet size casing for next year, of that I'm fairly sure.