I really wish that at least unity 7 is an official/semi-official flavour for 18.04. I'm perfectly happy with my workflow on 16.04, and have no desire to switch to Gnome, Plasma or anything else. None of the other alternatives come close enough to the simplicity, intuitiveness and stability of unity 7 at the moment. This is of course subjective, but without unity, I see very little reason to use Ubuntu over other distros.