This is a (very) rambling comment since I added things to it as I watched the video.
I think the state of the current Desktop UX is great. Maybe it's a local maximum we've reached, but I love it. I mostly use XFCE and there are just a few small things I'd like changed or fixed. Nothing that I even notice frequently.
I've used tiling window managers before and they were fine, but it was a bit of a hassle to get used to them. And I didn't feel they gave me something I couldn't do with a stacking window manager. I can arrange windows to the sides or corners of the monitor easily with the mouse or the keyboard. On XFCE holding down alt before moving a window lets me select any part of the window, not just the title bar, so it's just "hold down ALT, point somewhere inside the window and flick the window into a corner or a side with the mouse". If I really needed to view 10 windows at the same time, I'd consider a tiling window manager, but virtual desktops on XFCE are enough for me. I have a desktop for my mails, shopping, several for various browsers, several for work, for media, and so on. And I instantly go to the ones I want either with Meta+ (for example, Meta+3 for emails), or by scrolling with my middle mouse on the far right on my taskbar where I see a visual representation of my virtual desktops - just white outlines of the windows relative to the monitors.
Another thing I've noticed about desktop UX is that application UX seems follow the trends of website UX where the UX is so dumbed down, even a drunken caveman who's never seen a computer can use it. Tools and options are hidden behind menus. Even the menus are hidden behind a hamburger icon. There's a lot of unnecessary white space everywhere. Sometimes there's even a linear progression through a set of steps, one step at a time, instead of having everything in view all the time - similar to how some registration forms work where you first enter your e-mail, then you click next to enter a password, then click next again, and so on. I always use "compact view" or "details view" where it's possible and hide thumbnails unless I need them. I wish more sites and apps were more like HN in design. If you're looking to convert (into money or into long-term users) as many people as possible, then it might make sense to target the technological toddlers, but then you might lose, or at least annoy, your power users.
At the beginning of the video I thought we'll likely only see foundational changes when we stop interacting with the computer mainly via monitors, keyboards and mice. Maybe when we start plugging USB ports into our heads directly, or something like that. Just like I don't expect any foundational changes or improvements on static books like paper or PDF. Sure, interactive tutorials are fundamentally different in UX, but they're also a fundamentally different medium. But at 28:00, his example of a combination of window manager + file manager + clipboard made me rethink my position. I have used clipboard visualizers long ago, but the integration between apps and being able to drag and otherwise interact with it would be really interesting.
Some more thoughts I jotted down while watching the video:
~~~~ 01:33 This UX of dragging files between windows is new to me. I just grab a file and ALT+TAB to wherever I want to drop it if I can't see it. I think this behavior, to raise windows only on mouse up, will annoy me. What if I have a split view of my file manager in one window, and other window above it? I want to drag a file from the left side of the split-view window to the right one, but the mouse-down wont be enough to show me the right side if the window that was above it covers it. Or if, in the lower window, I want to drag the file into a folder that's also in the lower window, but obscured by the upper window? It may be a specific scenario, but
~~~~ 05:15 I'd forgotten the "What's a computer?" ad. It really grinds my gears when people don't understand that mobile "devices" are computers. I've had non-techies look surprised when I mention it, usually in a sentence like "Well, smartphones are really just computers, so, of course, it should be possible to do X with them.". It's such a basic category.
Similarly, I remember Apple not using the word "tablet" to describe their iPad years ago. Not sure if that has changed. Even many third-party online stores had a separate section for the iPad.
I guess it's good marketing to make people think your product is so unique and different than others. That's why many people reference their iPhone as "my iPhone" instead of "my phone" or "my smartphone". People usually don't say "my Samsung" or "my $brand" for other brands, unless they want to specify it for clarity. Great marketing to make people do this.
~~~~ 24:50 I'm a bit surprised that someone acknowledges that the UX for typing and editing on mobile is awful. But I think that no matter how many improvements happen, using a keyboard will always be much, much faster and pleasant. It's interesting to me that even programmers or other people who've used desktop professionally for years don't know basic things like SHIFT+left_arrow or SHIFT+right_arrow to select, or CTRL+left_arrow or CTRL+right_arrow to move between words, or combining them to select words - CTRL+SHIFT+left_arrow or CTRL+SHIFT+right_arrow. Or that they can hold their mouse button after double clicking on a word and move it around to select several words. Watching them try to select some text in a normal app (such as HN's comment field or a standard notepad app) using only arrow keys without modifiers or tapping the backspace 30 times (not even holding it down) or trying to precisely select the word boundary with a mouse... it's like watching someone right-click and then select "Paste" instead of CTRL+V. I guess some users just don't learn. Maybe they don't care or are preoccupied with more important things, but it's weird to me. But, on the other hand, I never learned vi/vim or Emacs to the point where it would make me X times more productive. So maybe what those users above look to me is what I look to someone well-versed in either of those tools.
~~~~ Forgot the timestamp, it was near the end, but the projects Ink & Switch make seem interesting. Looking at their site now.