VRM Phases are like tiny power filters which clean up variances in the power delivery to the GPU. Basically, the GPU board is fed 12v of power but the GPU needs far less than that (usually between 1-1.3v). What the VRMs do is phase the power down from 12v to the required 1.xv. Each phase step cleans the power to a larger degree and ensures less vDroop. VDroop happens when the supplied voltage drops unexpectedly. Such drops cause stability issues in the operation of the GPU which are more apparent when overclocking.
This means that NVIDIA have decided to omit one phase which results in a higher chance of vDroop on a card which has a high operating GPU frequency. This inhibits overclocking on a board being sold based on marketing fluff claiming that it is well engineered. Basically the marketing is false.
NVIDIA are cutting corners in order to improve their profit margins whilst also charging a premium tax on early adopters.
Um no. Clearly you dont have a good understanding in this field neither do most of the posters which is ok because I can explain it.
The VRM is basically a buck converter. So that one can step down (otherwise known as "bucking down" i.e buck) the 12V to what ever the voltage the GPU requires. This could be between 1~1.3V as you have said.
Now normally, having 1 buck converter is enough for most applications. But because the GPU requires alot of current (100~300A full load), you need duplicates of the same buck converter to satisfy the power requirement. Or else you'll end up with very very large components especially the DC inductor otherwise known as chokes (the large square things you see on the board - they come in all sorts of sizes/shapes/materials btw).
The converters are synchronized to share the load, and the number of buck converters you have are often referred as "the number of phases". E.g. 3 would mean 3 buck converters.
Now performance of these are normally judged on the following (alright there is ALOT more than this but lets keep it simple):
1) Output power capability
2) Output ripple voltage (also output noise)
3) Cost (for obvious reasons)
Output power capability is often dependent on the number of phases and how beefy the components are. More phases means more output power can be delivered to the load. More beefy the components are (they can handle more current with good electrical parameters like low on resistance) the more output power one phase can deliver.
Output ripple voltage really depends on how well the circuit has been designed (even if they are all doing the same thing). Using expensive components can help but best performance comes from the design equations themselves. I remember from that video presentation they had showed how they reduced the output ripple noise by half which means they really did their homework.
You talk about vdroop, but it essentially means how the buck converter copes with load steps. You'll see these spikes and dips when the load is constantly changing (150W to 50W, 20W to 200W etc). The number of phases has NOTHING to do with this. This is purely dependent on how well the feedback loop is designed of that converter i.e. how well it reacts to the sudden change of output load.
The conclusion I'd like to make is that, more phases =/= robustness or better. Your idle power consumption could actually be worse. The only primary benefits you'd get is that the heat is more spread out and you have the ability to supply more power to the GPU if it requires. Some of the downsides would be that having more phases could result in more output noise which of course isn't desirable (this one is arguable). The overall efficiency might be worse off too but that too depends on how well its designed.
However the primary point I want to make is that "Phases" aren't reflective of the actual performance of the VRM in terms of how clean the output voltage is, or how well responds to step loads.
So claiming that they've gimped something because you see that not all components are soldered on is quite a rookie thing to say if not ignorant (actually its quite funny). There is much more to it than what the un-trained eye is telling you. If their slides showing the oscilloscope wave capture + the efficiency curve is true, they've done an excellent job without having to use all that fancy components that the AIBs like to flaunt (its literally meaningless, well in my view anyway).