I have nothing against the default Ambiant-MATE theme, but would it be possible to bring back the classic Ubuntu Ambiance orange theme in the next release as a option?
There are many tutorials online describing how to accomplish this on your own. Perhaps the most comprehensive is http://askubuntu.com/a/760249/58618.
It might be a nice feature to just apply an included theme to revert back to the Ubuntu Ambiance theme. The Ubuntu Dark Mono icons are still included in 16.04, but for some reason the theme is not. Or is this not possible due to legal demands?