Interesting video; very informative. Gives me some nostalgia for Unity.
I used Ubuntu Unity for years and really liked it. (I was probably the only PLUG member who did.) It did things differently, but logically. Canonical had good reasons for the vertical dock, shifting the window controls to the left side, the HUD feature, etc. But when they abandoned the development of Unity and switched back to Gnome, I saw the handwriting on the wall and switched as well. Canonical modified the Gnome look and feel in Ubuntu enough so that adapting to it from Unity was pretty easy. For awhile I did have the Unity desktop added so that I could use either desktop. After awhile I didn't see any point in having that option, and I haven't installed Unity in years. Not that it isn't a good desktop. But Gnome is just as good for me.
The big Unity feature missing in Gnome is HUD (heads-up display). What that does is give you easy access to commands buried in menu layers that you might otherwise have difficulty finding. It's a good feature, but I rarely used it so it wasn't a good reason to retain Unity.
In my opinion, the most important feature that Unity brought with it is the vertical menubar (as a default with no option to change it). I think that this is the feature that turned most former Windows users off, but it makes a lot of sense when your display is landscape, as it makes better use of the pixels available to you. The feature was also available in Gnome 3 with the help of an extension which made the menubar always visible on the desktop. But in the past, it wasn't standard in any desktop that I know of. (Today, MxLinux also has it as standard.)
Presently, when I use or try out other distros, the first modification I make to their default desktop is to move the menubar to the left side of the display. This is easy to do in almost any distro I have tried, including Mint Cinnamon and Manjaro KDE. Are there any of you out there that put your menubar on the left side?