"It's the Economics, Stupid... "
No disrespect, Andrew, but the issues with W10 go far, far, deeper than interface design. As I see it, there are three major problems:-
1. Users Have Become the Product
With W10, Microsoft elected to get on the "free product" bandwagon and turn their user base into their product, "selling" their community to advertisers and market research analysts. Selling your users down the river is not a good way to make a popular product.
2. Leasing To Extremes
Rather than charge users a one-off fee for the purchase of their OS, Microsoft aim to make money through a range of subscriptions, such as charging people to disable advertising in the previously "free" desktop games. using this model I expect people to end up paying far, far more for their OS than they would for a one-off purchase, because the payments could be levied for years. For example, the "annual fee" model for disabling advertisements in the "free" games is such that in 2 years Microsoft will recoup more revenue than they would for charging a hardware vendor the [typical] $15-$25 license fee for the OS. So users will end up paying *more* in cash terms for a "free" product.
3. Windows is no Longer an OS
Anyone who has taken a basic CS course would quote you the function of an Operating System as: "an abstraction from the hardware, task scheduling, memory management and resource allocation" and precious little else. Microsoft seem intent on fooling around with the "OS" in attempts to compete with i.e. GNU/Linux, but the net result is that the result is actually *less* effective than it would be if they just thought of it as an OS...
I'm sure that the UI is relevant to the perception of less technically astute users, but the bottom line is that MS have lost the plot with W10. I can only hope that the world wakes up to this sooner rather than later, and that we can have a Windows 11, which would be Windows 7 with a tidy up and the latest DirectX please...