Personally I don't like the direction they went with spyware, removing a lot of the windows update controls and introduced a couple of extra steps when it comes to working with the computer.
None of the old interfaces are gone, just disabled. I re-enabled all of them , since I hate the new one as well. Especially the system control panels, which hide quick to access things like adapter settings behind awfully laid out submenus.
First thing I do when I install Win10 on any machine (half of it by script I wrote), is uninstalling all cortana, xbox, search index, telemetry, windows defender, etc. -services, -files, purging directories, disabling windows update service after a manual update, fix sizing the pagefile and disabling superfetch and the whole prefetch sub system.
Only then am I happy and everything boots fast, runs fast and never slows down.
I don't exactly agree with windows 10 being the main offender here, since this stuff did slowly get introduced when we made the jump from windows build 5 to windows build 6 with Vista. Feature creep was always a thing, it was just in the background up to Win8. Many features are really smart in the context of a laptop and low end systems, but with high end workstations it get's only in the way of performance.
But other than that, each new release did introduce at least something that made a general improvement, regardless of the main target device group.
For me with windows 10 it actually was not compressed desktop background images as an optional windows 10 regestry edit :D
