Unify and Make Configuration and Server Management Tools Orthogonal and Friendly
As a server manager, I often wonder why there can't be One Configuration Tool to Rule them All. Then I think about that famous XKCD cartoon where there are 6 competing standards (or ways in windows to configure your network) and then someone comes up with the Grand Unified Plan rev 12, and at the end there are now 7 ways to do everything.
So given that you can't drop the control panel, ever. Given that server manager is here to stay, given that there are vertical products that exist inside and outside Microsoft to unify the mess, all I can say is that the current state in Windows Server 2012 R2 is horrible, and that things didn't get any better for me when I look at Server 2016 RTM bits that just dropped.
ON desktop, adding and removing windows features (say, IIS bits and pieces) is unified into a single dialog with checkboxes. Easy right? Now let's look at Windows Server. Some bright spark decided to have two different UIs for add feature (IIS -> add webDAV) and hid the remove feature under a pulldown menu in server manager. I frequently have to google because of these horrible user-hostile non-orthogonal UX decisions.
I hate, hate hate using Windows Server's GUI. Hey Cortana, can you tell me where Microsoft's expert UX team has moved the feature I need in this version of windows and give me a retrospective on how this continuous improvement in Windows server experience has lead to this pessimization?