> I'm having a really hard time coming up with an OS feature introduced in a full OS upgrade within the last 10 years that I actually want.
- Live Photos. I won't consider any device that doesn't have something analogous, now. They're magical. Non-kid-havers may feel otherwise, but making every photo I snap of my kids a "Live Photo" is one of the most important improvements any technology thingy has provided in my entire life. (I think these are under the 10-year line? Very close, if not)
- Transparent OCR and text selection in images. The first time I used an image for a couple full minutes, copying text out of it, before realizing only when I went to share it with someone that it wasn't a PDF but a PNG, was when I knew this had to be a table-stakes your-OS-is-incomplete-without-it feature for me. Sure it could just be a feature of some program I've got installed, but having it in any native image view is way better than having to open some specific program to use it, a thing I could long have done, but never did. Making it first-class, fast, and transparent to the user, makes all the difference. I rely on it all the time now.
A couple off the top of my head.