It was the application of better concepts from both OSX and Windows. That was it strength. Top menu (better mouse usability), HUD (better keyboard usability), grid virtual desktops (better visual muscle memory), and so on. Nothing there was new or unique. But it was more ergonomic than the alternatives now.

I still miss the HUD, and the reason I use Gnome is support for autorotation, and other hardware features. And the fact that Unity now is a dead end.

It seems you did not use Unity, and you were part of the group of people who caused its demise by endlessly complaining.