So I’ve used the Pop Shell extension. It’s really neat when you have a bunch of little windows like terminals and file browsers open. 95% of the time it’s actively annoying though. I appreciate that it’s on a toggle so I can use it when I want it. The proposed mosaic mode doesn’t seem terribly different, and has the same problem where it just randomly moves things around breaking my association of “where I put that”. Most of the time I really need the spatial aspect, and am willing to manage a few windows by hand to get it.
Also: Joining half screen windows into a single unit?! Please don’t do it! D: Augh! Apple did that on OS X about the time I left and I absolutely hated it. It was so actively bad. :(