I understand all of your concerns that you conveyed in your video. All I can say, (and all we can hope for) is that this 9926 build is still a very early build, and that the final product will be every thing that we loved about 7 and 8/8.1, and so much more... provided that we all collectively voice our concerns and constructive criticism through the feedback program.
When I look at the 9879 build of Win10 TP which I still have up and running on my laptop, and compare it to this latest 9926 build I have running on my desktop, the 9879 build seems so much more "robust" and closer to finished than the latest 9926 build. (to me anyway) This leads me to believe that they've obviously rebuilt it from the ground up, and "re-seated" the core of the OS, while adding the new features along the way (Cortana etc), and still have much work to do to bring it up to where we felt it was closer to "consumer ready" by using it. In other words, I really feel like the 9926 build is in a lot of ways a little more premature than the 9879 build was. Be patient, and use that feedback app... we'll get there!
btw.. I don't think anyone else noticed in your video, but you've got one of the uber rare "prototype" Type cover keyboards for your Surface... I'm jealous! And I don't even have a Surface anymore lol