Full disclosure: I work at Microsoft but outside of Windows.
> poor upgrade/reinstall behavior resulting in lost licenses
I have never experienced this. If you bought Windows 10 straight up (or your computer came with one) then you have a product key you can use, just like before. If you upgraded from 7/8 or are in the Insider Program, then you get a digital entitlement to your Microsoft account which gets restored automatically when you next sign on. http://windows.microsoft.com/en-us/windows-10/activation-in-...
> overly complicated licensing structure
There are two editions for consumers: Home, and Pro. With the differentiator being fairly clear from the name alone (home is for home users, pro gives you things you aren't going to ever use at home but might at work, like AD join). There are other editions like Enterprise and Education, but an end user will never even see them.
> forced integration of unrelated products
Cortana is a part of Windows. It started as a Windows Phone feature, and got brought over to desktop. There's nothing unrelated about it. Bing is integrated to Cortana because that's the backend powering it. It's like how Ok Google uses Google on Android. Using a third party provider would not give nearly the amount of insight it currently has, since the two teams can work together to improve results and the overall experience.
> integration of advertising into the OS (lockscreen and wallpapers)
Spotlight has shown one ad that I am aware of (Tomb Raider). Otherwise, it gives you curated images rotated every so often. Your wallpaper does not change, that is not a feature of Spotlight. It's also completely disableable; you just set your own image.