All versions of Windows have required some tweaking to make them useful, some more than others - I see it as a challenge. Yes, Windows 8.1 and 10 are the most challenging versions, mostly because I want to avoid the entire "Metro/Live Tiles/Windows Store aspect, but free programs like Classic Shell make that easy and quick.
Yes, all versions of Windows have required tweaking, but making 10 work... isn't going to work. The crappiness runs too deep.
For one thing, the monolithic updates. This article is about how they're coming to Windows 7 and 8 too, but there is a mitigating feature for those of us on 7. It's in the extended support phase, which means no new features, just security and bug fixes. Those are the only updates I really want, so as long as MS sticks to those two things, I am okay with update roll-ups-- though I watch them warily, as the telemetry updates and GWX adware were most definitely not bugfixes or security updates, and we still got them during extended support.
With Windows 10, ALL of the updates are rolled up, and they're cumulative. And now that this is the last version of Windows ever, all of the "features" MS wants us to have will simply appear one day on our computers. There's no official way to avoid them, and if you use an unofficial way, you have to skip ALL of the other updates from that point forward. All of the bugfixes, all of the security fixes. You'd be better off with 7, which won't start requiring people to run unpatched for four more years.
Sorry, MS, but after what you have pulled in the last year, I don't trust you enough to give you a never-ending book of signed but otherwise blank checks to do whatever you want with my PC. Not going to happen... not now, not ever.
The telemetry... well, I don't think MS is rooting through people's hard drives looking for something juicy-- yet. The point is that they can, because they can push any update out they want, and their EULA gives them a broad array of rights to your data if they decide to do some mining. Yes, this can be blocked as part of your "making it useful" challenge, but having to even do this is unacceptable.
An OS, by its very nature, is very close to the user and the PC itself. It needs to unerringly and unquestionably serve only one master, and that is the PC owner (who is usually also the user in the context of home PCs, so for this post, the two are used interchangeably). Windows 10 fails that test miserably. It wouldn't even be acceptable for an OS to serve the user first and the software company that made it second; it should serve the user first and to hell with everyone else, including its maker. Windows 10 serves MS first and its users last, at least in the individual license versions.
When the users say they want all of the telemetry off, and MS comes back with a response that you can turn MOST of it off, that's not good enough, even if we do have the ability to block it (for now) with third-party applications. When we say we want the rest of it turned off and we get back excuses about why it is harmless and why MS needs it, it's clear whose needs are being served here, and it's not ours. The point is that I, as the computer owner, have decided I want it off, and it doesn't matter if I have what MS considers a good reason or not. If I say I want telemetry fully off because the orange tree in my backyard will come to life and throw oranges at my house otherwise, that's a good enough reason, because as the owner of the PC, my wishes are the only ones that exist. It doesn't matter how anonymized the data is or how important it is to MS... not even a tiny bit. Not on something that is as close to all my personal data as the OS.
MS obviously does not get this, and that itself is part of the problem. They have the wrong attitude, and that infects every bit of every product they offer, and it's exactly why people deride Microsoft for every possible thing they do. MS has earned this cynicism; if there is any possible interpretation of any move MS makes that would benefit them at the expense of others, it is sensible to assume that is the motivation until proven otherwise. It's not paranoia, as the MS shills claim. It's observing how MS has behaved in the past and using that to make an educated guess about what they are up to now. If Bernie Madoff was released from prison on a technicality, and the first thing he did was to set up a securities fund and started looking for investors, it would not be paranoia to assume he was looking to defraud people.
Now, about that Windows 10 UI: You can do the usual theming to get rid of the white monstrosity of the default theme (I haven't seen the dark one yet), but an installed theme doesn't affect the UWP bits. Like you, getting rid of all of the Metro-ish stuff would be high on my list... but you can't get rid of all of it, because a number of system features use it and have no traditional Win32 equivalents. (The settings menu, for one). There's no way to get rid of the "app" appearance in that case (and there are others, and probably more to come in the future).
When I had Windows 10 installed on my test PC, I found some powershell scripts that would forcibly evict Cortana, Edge, Windows Store, and every other remaining "app" that CCleaner could not remove. Everything worked fine after that in my limited use, but with 10 under continuous development, how long will that be true? How long until some part of the OS will fail to work without the bits I won't allow to live on my computer?
That's the thing with 10... you can hack it and try to get it resembling a reasonable OS, and you may have some success, but for how long? MS doesn't want you to uninstall their stuff; they made it impossible to do through normal means on purpose. They don't want you blocking their updates or their telemetry. And they have the keys to your kingdom! They can break your hacks and workarounds any time they want... and they WILL want if people start doing them in any way that catches their attention (and with the telemetry, they will catch a lot of things).
A lot of Windows users have criticized Linux as being too "fiddly" for them for daily use. I've recently started using it in a dual-boot setup with 7, and I certainly can see that as true for a lot of people (and I have had to do fiddly stuff myself, though I must say I have with Windows too)... but Linux is slowly improving, while Windows is getting worse at breakneck speed. If you have to fight your OS every time you get an update in order to thwart it from performing its primary mission of serving Microsoft's needs, is that somehow acceptable? At least in Linux, when I do get a problem fixed, it stays fixed as long as I want it to. Future updates may break my fixes, but I can control, with granularity that Windows can only dream of, which things get updated and which do not.
To those who say 10 is inevitable... well, no, it's not. I don't know what I will be using on my PC in five years as far as Windows, but I know it won't be Windows 10 if its in its current form. Nope, nope, nope. I'll put 7 in a VM under Linux (or even XP) and run that if I have to for certain programs, but I'm not touching Win 10 with a ten foot pole unless it does a massive turnaround. I don't anticipate that happening, so I am working on transitioning to Linux full-time.