Actually Vista wasn't as bad as people claim it was. Windows 10's start menu needs more customization added to it. We need to be able to make it as tall as we want. Not just 1 cm. taller. The Xbox app needs to be a optional install. It's only useful if you have a Xbox One. The Mail, Calendar & People app's bug needs to be fixed.
Considering it's almost May and 10 is supposed to rtm this summer, it's time for Microsoft to get off their butt's and get the various companies releasing driver's for 10.
What point is running 3DMark and comparing 10 to any other Windows version, if you can't enable sli or crossfire in 10 it permanently puts our monitors to sleep. Sorry Microsoft your generic, nVidia, AMD and Intel display driver's don't cut it.
They also need to fix current bugs, before releasing new features, that add more bugs.
If they can't do any of that 10 will fail.
Universal Apps are a joke so far. They need to get the app's/programs in the Store that people use. Things like CCleaner, SearchEverything,CPU-z, GPU-z, etc. Until they do that, the store will always be a joke.
App developers have either left Windows, Windows Phone all together, or they've just stopped caring about releasing updates to fix bug's in their apps. Collector is a perfect example, since WP 8.1 the app got buggy. I contacted the developer and they're only interested in Android and IOS, not Windows or Windows Phone.
Now, Microsoft is making Windows Phone work on Android phone's. That's the stupidest thing Microsoft can do, especially when they want you to buy their low-end smartphones or high-priced tablets.