Another comment suggests that there's "fierce competition" in the version control space. In fact, I think that there's fierce collaboration in the version control space! Durham Goode from their team gave an interesting talk at Git Merge 2017 about how they're using Hg and some of the interesting user-experience tools that they've built on top of it: https://m.youtube.com/watch?list=PL0lo9MOBetEGRAJzoTCdco_fOK...
I don't personally prefer Mercurial (I like Git, as you might have guessed), but I think that there's some opportunities to learn from their user experiences and perhaps add or improve some high-level Git commands.