I think maybe Microsoft is going for small screen compatibility with this new, severely minimalist aesthetic. I find that and all the phone-related crap in Windows 10 obscurely annoying. I use Windows with large monitors, dammit!
Well, anyway. There's two, maybe three different menu philosophies at work in Windows 10. Windows 7 has probably two: whatever the Start menu does, and then whatever complex explorer thing opens up afterward. Windows 10 has added in phone style "simplicity", with large arrows and simple-minded, barely informative option/explanation screens. Once you get used to it, and to the oddball idiosyncrasies of the back arrows, maybe it's okay. (Back arrows don't always take you back to the screen you came from - sometimes, often, particularly in settings stuff, they take you back to a the more general category of settings the particular one you navigated to comes from - it's disorienting.)
So there's that. And there's how opaque Update has become. There's no longer a Windows Update link in the Control Panel, for instance. If you want to find what's going on, you have to search "update" or something similar. And if you don't have the "Professional" or "Enterprise" edition of Windows 10, you might as well forget about searching, because you're not controlling those updates anyway. Having an operating system doing sometimes large scale downloading, and then altering itself, in the background is... worrisome.
Meanwhile, on more simple usability stuff: installing languages is easy. I forget how I did it, but installing a Chinese language IME was considerably easier than any other Windows I've encountered. I think I just searched "language", discovered an option to "Add a language" and selected Chinese. Boom, done. (Maybe. I think it actually downloaded something from Windows Update, but I'm not sure.)
Lastly, I'm really liking Microsoft Edge as a browser. It's super-minimal, intuitive, and nippy. Unfortunately at present there are no Extensions, so no Adblock and no script controls. Apparently they'll be available around "autumn" (presumably North American autumn).
So ultimately, will I upgrade my main computer now? Short answer: no. Long answer: most people upgrade only when they buy a new computer, so who's going to rush anyway, right?
Windows 10 is the future, probably. It's probably the last numbered Windows there will ever be. In the future it'll all just be "Windows", and you upgrade to whatever version is going whether you like it or not. Or so goes the theory. For that to truly work though, Microsoft has to somehow wind up supported by third-party app creators, people who invent such things as ClassicShell. Ordinary users would customise their Windows experience and boom, everybody happy. It hasn't happened yet though, and it isn't what traditionally happens when you have a Windows machine. So, we'll see. Not even Microsoft is expecting everyone to rush right in and make the change. That "free" upgrade they're offering Windows 7, 8, and 8.1 user is available as an option for one whole year. But maybe in the end it'll probably be worth doing eventually. I actually don't know what the benefits are.