The problem was, they need to put a LOT of polish in to reach OS X levels of usability, and they didn't look like they were doing that, they had some nebulous dreams of making a unified mobile/desktop interface instead.
There isn't anything in particular I'd suggest to them, because they need improvements just about everywhere. Say, is the network manager actually usable these days? When I switched it was easier to just disable it and move along.
And the main elephant in the Linux room right now is systemd. Low level Linux is basically being taken over by an incompetent developer who doesn't understand the Unix philosophy of software design and can't deliver working software anyway. He's the author of the abomination called pulseaudio - back then it was required to uninstall/disable it to have sound again. Now, software written by him is becoming a dependency of almost everything - he is trying to replace all the Linux infrastructure layer with his ideas. Sorry, I see no reason to take a look at Linux on the desktop again.
Systemd in Linux has the same role, as Launchd in macOS. Some aspects of systemd were inspired by launchd and SMF.
Interestingly, it is a good, useful thing that contributes to polished experience when it comes to macOS, but for some reason, when someone does equivalent for Linux, it is suddenly a bad thing, just because it is different than in the past and moves the polish and experience with Linux to a higher level?
Unix philosophy aside, Pottering can't be trusted to provide working software...
If you have such problems, that your machine crashes and loses filesystem data, just redirect it to the syslogd and go on.
Before Ubuntu, if you expected to get a build of a typical popular Windows program/game you would get laughed at. Now it's virtually expected. That's not failure.
systemd is not as much a matter of controversy as people want it to be. If it was, you would see people like Linus rejecting it, but they haven't because it's not a major factor right now.
You've just made one of the errors discussed in http://uselessd.darknedgy.net/ProSystemdAntiSystemd/ .