Though I end up just using LaTeX (with memoir class) most of the time, I've always thought LyX hit a sweet spot between strict enforcement of document structure and forcing people to write markup.

For the life of me, I can't figure out why LyX doesn't exist as a collaborative google docs style web app.

I like writelatex.com lately.

Still has the problem of needing to talk collaborators, advisors, and other folk into learning LaTeX. In the alternate reality of my dreams, all people that I work with in an academic environment would write LaTeX and collaborate via GitHub.

I've personally been thinking about some sort of GitHub, LyXified markdown browser plugin, in which collaborators' changes get committed to a separate git branch. Then I die a little inside and soldier on.