I have occasionally thought about a system where you can zoom and scroll a view on a window, but without telling the program that you're doing it. So for example, you could crop into say firefox and only show the actual page (completely cutting out toolbars and such) without it resizing itself. This is mostly of interest on smaller screens, but it'd still give you efficiency gains on a bigger screen.
1. Zooming with Ctrl++ or Ctrl+- will "tell the page" that it's being zoomed and it will reflow into the new viewport size.
2. Zooming with two-finger pinch (requires a touchpad) will zoom in as if magnifying the page. Content on the page will overflow to the right instead of reflowing.
Supporting an equivalent on regular desktop windows could be pretty useful.
The windows are almost always full height and you just scroll to next or previous windows in the Workspace. It reduces the spatial navigation to just one axis and works pretty well on ultrawides.
Alt tab often requires two things: 1) Figuring out how many clicks to away your desired window is, as they change 2) executing those multiple key presses correctly
When you compare this situation with a wm where you place or permanently bind certain windows to a number (eg messaging apps are always CMD + 0 for me) then you can see how you can grow to prefer the certainty, there's no more fiddling for the window you're looking for.
Windows actually sort of had this feature with windows + numbers as that focused the window by order on the bottom bar, but lately with window groupings and things like that it breaks for common use cases such as multiple browser windows.
How is this related to tiling managers if you can do exactly the same thing without them in your generic shortcut utility?
There is also a downside of this certainty: you always need to keep in mind the two recent apps you're working with (for some uncommon apps you wouldn't even have a predefined CMD+0) and then your CMD+0 wouldn't help if you have multiple messenger windows and need to switch between two
Besides, I find the simple tiling offered by the stock GNOME Display Manager, which is similar to the way I use xmonad, good enough. Given that GNOME has great support for floating windows, that is perhaps an option you should look into.
The ability to overlap is also actually pretty valuable for me. Often I don't need to see a whole window, just the pertinent portion, and sometimes window edges peeking out from behind my browser window act like post-it note style reminders.
It's nice to be able to snap windows into grid positions on occasion (preferably without aero snap, the animations for that erroneously trigger way too often on multi monitor setups) but it's easy enough to bolt that onto a floating WM.