Last time I used 11 it had a few things which are deal breakers for me.

1. All windows of same application are grouped. In 10, you can have it group them never or only when task bar is full. On 11 you have no option. It takes an extra click every time you want to cycle to a specific window.
2. Seconds on the clock are gone. I use that on 10 occasionally and want it back.
3. Context menu in explorer was changed and is way more frustrating to use. My biggest gripe is the keyboard shortcuts were changed for no reason.
4. The ribbon menu is going away for nested menu system. Ribbon is objectively better for repeating multiple commands.
5. Gaming performance is worse, specifically VR.
6. UI/UX changes, some are good, some are bad. It’s not a polished OS with inconsistencies everywhere. In 10 at least they tried to make each level of the UI consistent with itself. 11 is just a hodgepodge of useless shit.