Of the above, I would like to point out that I do agree most Linux systems, Ubuntu MATE included isn't exactly a drop-in replacement; it is beyond stupid for people to think the system can function exactly like ones they've used prior, down to its advanced features. When I was mentioning about workflow and dated interfaces, I was meaning to highlight spatial relativity per-task.
Of course, there are some tasks that Ubuntu MATE cannot exactly replicate — They're exclusive to their host systems. While I think that yes, the system has to be different, people expect things to be in a certain place. Even with keyboard shortcuts, people get into a pattern; a rhythm, a flow.
Satisfying the flow should be prioritized for people getting into a Linux system for the very first time. Before the zeitgeist even bothers with Ubuntu MATE, I would recommend it changes the applications they use on their current system to cross-platform utilities which can carry over into their new desktop, so not only is spatial relevance satisfied, but their expected requirements for the system's function is satisfied, even if not through the system software itself.
I would talk in-depth about how severe a loss it is that Linux doesn't do all of the games but then this post becomes less about response to an interface issue and more of a sociological issue.
One last point about Linux being "Dated"; I think because the entire userland was designed by nerds, for nerds, people who first encountered Linux under the impression that most tasks require a terminal a la the days of DOS don't even begin to consider advances of interface design which had made desktop environments like GNOME Shell, KDE and our most beloved MATE possible.