I think it was a mistake for Canonical to have chosen GNOME rather than KDE Plasma and in this video I explain why. Essentially it boils down to the fact that the vast majority of features in Ubuntu's Unity are already available in KDE Plasma, most of which are available by default. Canonical could maintain the switch to Qt that Unity 8 started, maintain the design vision that Mark Shuttleworth wanted all the while not having to hack on the code of the KDE Plasma desktop environment much and in some cases at all.
__Segment Index__ 00:15 - Why Ubuntu Should Use KDE Plasma ------- Unity Features in Plasma 01:03 - Unity Launcher 02:35 - Global Menu 03:18 - Left Window Controls 03:52 - Super Number Launching 04:23 - Top Right Indicators 04:33 - Sound Menu Applet 04:52 - System Menu 05:15 - Merge Panel/Titlebar on Maximize 05:51 - KWin No Borders is Awesome 06:13 - Recent Files in Dash 06:33 - Jumplists 06:41 - Alt+Tab Application Switching 07:08 - Workspace Switcher 07:28 - HUD (Heads Up Display) 09:26 - Prototype Unity in Plasma Package ------- 10:28 - End Screen