I think it'll be able to run PS4/XB1 ports at a reduced resolution but we'll see. 

PS4 games still look plenty nice on the Vita's 540p display even, 540p is 1/4 the pixels of 1080P. That means theoretically something in the range of 400-500 GFLOPS could work, there is LPDDR4 RAM that is 50-60GB/sec too ... that is easily more than 1/4th the bandwidth of a PS4. 

It could operate under one constraint in portable/battery mode and then consume more power in docked/home mode. 

Yeah this comparison is straight out bias. It doesn't take into account how the games takes or doesn't take advantage of each GPU architecture. Maxwell has been made to perform for current games, DX11 level games. AMD made GCN with forward thinking. When DX12 or equivalent, especially Async enable games are used, GCN matches if not overtakes Maxwell. Those benchmarks are irrelevant when a game is made specifically to take advantage of a console's hardware.
The only thing we can get from numbers is that Maxwell and Pascal are more power efficient compared to their GCN counterparts. This is ignoring image quality which I don't think anyone here talked about.

Also, about ports. You guys just can't say NX will run so-and-so port with scaled down graphics. Yeah, the graphics can probably be scaled down. But it's harder to do with CPU intensive games, you just cant scale down say AI or physics of a game, because doing so could change the gameplay and enjoyment of that game.

Doesn't work like that.

While the comparison and the research seem thourough, one should not forget that this is just one number. Remember the whole Resolution-Gate stuff a few years ago? This smells definitly familiar.
Considering the NX and its power according to the current RUMORS (important, please remember!) it is all but guaranteed to exceed the Wii U, while being a far way from NEO and Scorpio.
Even if Nintendo uses the X1, we must take into account their OS (being likely better optimised for Games than the Android OS of the Nvidia Shield), the custom tweaks to the chip, as they probably wont use the exactly same chip, and, well, the rest of the hardware?!
Ram, the actual screen resolution, power supply, possible cooling systems, all this will effect the Power Level.
Also there is the good possibility of Nintendo using the newer X2 chip as a base for their custom NX-Chip. This would, among other thins, mean the Pascal-Architecture which is much more Power-efficient, and the same Architecture that powers Nvidias newest flagship GPUs, the 1070 and the 1080.

If the latter is the case, and NIntendo uses X2, the power levels of XOne and PS4 are definitly in range, if they use X1 they still could come close enough to get ports without too much problems, or at least better than with the Wii U.

Its actually pretty interesting that many third parties are already saying good stuff about the NX, despite Nintendo not having said anything about it yet. If they had shown it at E3 this would be the usual BS everybody does everytime, but like this? Thats quite interesting and a probably a good sign for what is to come.

Graphical cards are more than just the flopcount, besides I doubt a handheld would have RAM and a CPU close enough to the Xone or PS4 for easily porting games. So the NX given Eurogamers rumours are true will most likely linger on exclusives.

We are talking about Nintendo here, I think their design is going to be custom. So custom that Neogaf will be spending weeks looking at chips X-rays figuring it out. Point being, the X1 is most probably a place holder for dev kids. Hopefully with the minimun specs nintendo has in mind. Thats my theory.

I think you are probably going to be sort-of right.

I think the chip will be semi-custom, I.E. Nintendo will take the chip and add a few things it needs/wants rather than drastically overhaul it.
As time goes on it becomes less feasible for platform holders to spend significant time, money and R&D building custom chips in this constantly evolving tech world.
Tegra is a good technological base, even if I do want something more substantual.

Pascal should be a good step up, but it still can't be compared to the desktop chips on terms of performance/watt/chip size.

The jump from 28nm to 16nm/14nm should result in 2x-2.5x the performance for the same power consumption if all the architectural things go right, Tegra X1 was built at 20nm not 28nm, so expect 1.5-2x at most, which helps shine a bright light on a Pascal based Tegra over it's predecessors. - Although it should still end up slower than an Xbox One.
And the Xbox One is certainly the ugly duckling of this generation relative to other platforms (PS4 and PC) in terms of graphics.

But we also need to put things into perspective.
The Xbox One released 3 years ago, based on technology released 4 and a half years ago, the NX is likely not to be able to exceed technology that released over half a decade ago by the time it launches. - Is that acceptable? Well, that is up to the individual, for me it's a resounding "no".

The interesting part is how the chip will be fed. If it's any of the current Tegra's it will likely be using slow dual-channel LPDDR4.
If it's the Tegra "X2" it could actually have GDDR5 if rumors of that chip having a GDDR5+LPDDR4 memory controller end up being true, if so, then it could certainly give the Xbox One a good run for it's money... And for some, that's certainly "good enough".