Desktop is core? Less talk and more action please. Quality from Microsoft has been going downhill in many areas. I'll make a quick list off the top of my head.
Timing is everything, which is why ending XP support now was a slap in the face to your core base of desktop users. A lot, and I mean lot of people still have XP even after the plug has been essentially pulled on it in an effort to force people into Windows 8.x. Many people don't like Windows 8.x for obvious reasons. Some people just don't need a new computer and aren't very happy being nagged that support has ended. Microsoft Security Essentials nagging on every startup is a poor user experience, annoying, and foolish. You can say it's about warning and protecting the user but many don't care and want to continue to use it anyway and that's their choice. So why nag them like some adware infection? Remember the boy who cried wolf? Next time they won't listen.
Windows 7 will often not update without failed update attempts during large batches of updates sometimes. This never happened with XP in the many years I've worked with it that I ever recall on clean installations. It happens on Windows 7 often. It's not fatal, but it's a waste of download bandwidth and time due most likely to poor update scripting on Microsofts part. Not enough testing and quality control. Still I prefer Windows 7 over all other versions.
Windows 8 updating is a nightmare. I can't update a customers computer the standard Windows store way without their password. I can't download an update and just apply it like a service pack and have to endure long download times and even longer installation times. Now I may be able to do an in place upgrade with an 8.1 DVD but that's still not as good as a service pack for many reasons. I don't like the Windows store, the start screen, or the ribbon bars so even if I would use Windows 8, which I will not, I'd have to put an older Wordpad on to eliminate the ribbon bar, a third party start menu which I don't use much but still prefer of the start screen, and an explorer replacement to get rid of said ribbon bar. That makes my out of box experience bad enough I don't want to do it over the many installs I would do during an OS lifetime.
That's just a few things. I have many more and not enough time to bother listing things like defrag name changes in Windows 8 so search won't find it correctly or other stupid annoyances. I'm never excited about changes for the sake of change without a good reason so even XP annoyed me in some cases at first, but never enough to prevent me upgrading, unlike Windows 8. So, don't tell me desktop is core, prove it. Until then I don't trust you, don't support your flagship product, or your business in general. You've annoyed me too much and I won't soon forget.