Heres my 2 cents... more like 2 dollars worth on this topic.
I hadn't really given much thought into GUI's until your video, but there were a few things I had thought of before that I like how you kinda all tied together nicely. I have really liked the idea of being able to customize my computer's gui to look like something out of Deus Ex or Half Life, but its not exactly done out of a want to be more efficient, more out of it just looking cooler visually. I doubt I'll be the first or last to recommend the program "wallpaper engine," which allows easy downloading and creating of moving and even interactive wallpapers, and is done through steam. Of course, it doesn't do much of the efficiency-improvement things you want, but I do think it is a lighthouse of sorts, and likely means that, though difficult to code through microsoft's burying of GUI code and constant updates, it is likely not impossible.
To expand into what I think the bigger picture is, I really liked how you included the footage of Tony Stark, as it would be my dream to be able to have that type of computer GUI tech. Augmented Reality may come in clutch for this. You mentioned in a video chat that you got a samsung odyssey windows mixed reality headset, which I have the exact same one. Windows Mixed reality headsets have a sortof virtual hub/desktop inside it, and you can even access every program on your computer, and it'll load up as a flat virtual screen floating infront of you. Now, this isn't something anyone would realistically use for work, but I think that it can sortof be the basis for how AR may look in the future, being able to open up windows infront of you virtually. Ipads and many apple devices already have some touch gestures, and expanded versions of that or the ones you showed in your video could be used in tandem with virtual windows or interfaces. You mentioned how "computers like their squares" in Deus Ex Invisible war, that may not even be a problem with virtual displays. I've heard both valve and apple are working on AR systems, so it may not be too long before we start seeing those.
Another technology that I think goes hand in hand with computer GUI and AR tech is Smart Home tech. I've always been a sucker for it, even though it's probably being used to monitor and suck money out of me right now, but thats cuz I really want to live like I'm tony stark. Besides, half the fun of AR is being able to control real life systems. I have an Alexa, which works really good with the smart lights I have connected to it, but I really feel like it is nowhere near it's potential. Like, I wish it could do more stuff to interact with my computer, or my wallpaper engine, but it just isn't quite capable. For example, being a big Half Life/Portal fan, I wanted to be able to set my alexa wake-up alarm to the "Aperture Science Wakeup" sound from the very start of Portal 2. The problem is, Amazon doesn't let you import or use any custom sound files, or import any music at all into your Library, as they made it so you can ONLY listen to music you bought through Amazon. And moreover, you can only use other streaming/music services if you have bought their premium packages, like Spotify Premium of Apple Music. So they have put a wall up in the way of allowing me to do what I want. And that's characteristic of the whole Alexa, and I can only assume for google home as well, experience. Due to the fact that these are corporations who don't like modding outside of making special skills for their devices, which can't do that much, and who have interests in making money, they have put some arbitrary limits on what you can do with your smart home devices. I'm no programmer, but I know enough to consider myself an "advanced user," and trust me, if you're an advanced user of many mainstream tech these days, you find the walls of limitations fast.
To get back to GUI's, heres what my dream would be; If I could get a super efficient and visually appealing GUI for my computer, that would be compatible with modern windows, that would be the perfect start. I'd want it to work across multiple displays, some of which perhaps being touch screen with IPad style gestures. Beyond that, have even more Virtual screens only visible in AR that I may even bring with me out of the house. My whole house would have a smart home system set up, but instead of the AI being done through the internet, and thus being house on Google or Amazon's servers, I'd instead have all of it within my own computer, and could therefore do anything I program it to do, and could use anything on my computer at it's disposal.
so uhh... I think I kinda got off topic