captain_video, I agree with everything you have said. There are many ways different ways to do HT media serving. Everybody has differing requirements.
I use MKV's for some purposes as well. It depends on what I am looking to achieve for the given task.
As a former (retired) IT professional, I have built, maintained, and used RAID in the past, in the form of the ZFS file system on Solaris 10.
At home, I use RAID 0 on a HighPoint Rocket 640L Lite Version 4-Port PCI-Express 2.0 x4 SATA 6Gb/s RAID Controller for real time video capture.
If I were to build a media server of your scale, I would most likely go Linux / ZFS.
I use Windows 8.1 almost exclusively because stability is paramount.
I wouldn't touch Windows 10 for any media server or HTPC, unless there was no other option.
I do have a couple of laptops in the house with Windows 10 and my wife's desktop has it installed. It's a constant battle to keep them stable, what with the buggy updates, and Windows thinking it owns exclusive rights to modify device drivers unless told otherwise.
I currently have 3 HTPC's in my HT. One optimized for Blu ray, one optimized for 3D, and one optimized for UHD. They all feed a JVC DLS-RS57 projecting on a 12' 2.76:1 screen with an Isco 1.5X anamorphic lens. A Denon AVR4500h handles the audio and video switching. I do all of my serious viewing in my HT, with very little video streaming to other Displays in the house.
Unfortunately, for full ycbcr422 10 bit support, I may eventually have to go to windows 10 for my UHD optimized HTPC. But you can bet updates will be deferred to the max (or totally disabled).
It's amazing how a hobby can turn into a full time occupation,