So, changing the UI on Windows 10 would make it not utter garbage?
It would be a good first step, but as long as there is still "Windows as a Service" and its insane update schedule, as long as users are denied full control of updates like we had in Windows 7 or 8, as long as there is not a master "telemetry off" switch that really does what it says on the tin (no "minimal" here; when I say OFF I mean OFF) and stays put where the user sets it, Windows 10 will still be garbage.
I don't want any apps on my PC. I run programs... you know, those things that end up being placed in "\Program Files," which is named that for a reason. An "app" is a program designed for a mobile device that has limited resources (local storage and screen space being most notable, though processing power, RAM, and GPU power are also well behind typical "regular" PCs) and that is written to cope with the handicap of not having a hardware keyboard or pointing device.
None of those handicaps that require an "app" to be so limited apply to my PC, so they have no reason to be on such a relatively robust device. I don't need them, I don't want them, and I won't tolerate their presence, no matter how much Microsoft's marketing department tells me it wants me to have them. My PC exists to serve my needs, not those of Microsoft or anyone else.
As long as "bring back the UI from $older_version_of_windows includes deep-sixing everything UWP or Acrylic and returning to a full Win32 UI, these are the other things that need to be fixed before 10 stops being complete crap, Microsoft.
I don't know if I would ever go back to Microsoft-land after what they have done. Even if they saw the light and fixed all the things I've highlighted here, I don't know if the trust that has been lost can be overcome. I never wanted to leave Windows; I've been using it since 3.0, so it's been my "home" for more than a quarter of a century. It's never been perfect, but I have spent most of that time thinking that it's really pretty decent, particularly in its NT-derived forms. It has its flaws, of course, but all things considered, I found XP and 7 to be the best choices for me, ahead of Linux and OSX/MacOS.
Windows 10, though... no, just no. As Hall and Oates said, "I can't go for that." As the old adage goes, with appropriate substitutions, "I didn't leave Windows... Windows left me." From the start of my relationship with Windows, it was designed strictly for the PC platform, including a hardware keyboard and a mouse, along with a reasonably large screen (though in 1990 that meant 14 inches). That's what Windows has always been, and what I still expect now. The last version of Windows built to those specifications was Windows 7... after that, Windows left me behind in pursuit of mobile users that it could never get (and even though MS has conceded loss in that market, it still insists on staying the course).
I'm not getting on the Windows 10 train, Microsoft. I know you think that you're so big that you can bully and force people to accept the utter crap you offer, but that doesn't work on all of us (and over time, I would guess most of us will tire of it). Thanks to your Windows 10 efforts, Microsoft, I'm typing this from Linux right now on my laptop, a PC that now spends 97% of its time in Linux (Windows is still there as dual boot, but I hardly ever use it). I still have five years of life left in Windows 8.1 (heavily modified to get the stupid out), and I might still be using that if you hadn't pushed "the last version of Windows ever" so heavily. I thank you for making your intentions so clear, Microsoft; with GWX and the continued efforts to force Windows users into the Windows 10 prison, I can clearly see there's no future for me with Windows. As long as the insane update schedule and permanent beta quality rule the day, Windows 10 doesn't even exist for me as an option.