Use latex with git, say on github. You get all those features and more, just with a UI that separates them from the document. I've collaborated on notes using

Use latex with git, say on github. You get all those features and more, just with a UI that separates them from the document. I've collaborated on notes using latex before on github and PR discussions, inline comments, and git collaboration features like branching, descriptive commit messages and diffs, etc. are awesome for productivity. That said, everyone will need to know how to use latex, git, and GitHub, so gdocs certainly has a simpler workflow.