I have been working on tracking changes over the past few months. The basics are ready - tracking changed inline content, removed items like figures or tables and various user requested changes to lists. There are still some things missing though, like the tracking of formatting changes and headlines turned from level 2 to 3, etc. .
I've studied LibreOffice Writer and Microsoft Word and come to the conclusion that these also just offer tracking up to a certain degree. And the most important are changes to texts. Changes to a lot of formatting is simply not tracked. In the continuum between tracking everything perfectly and on the other hand making a user interface useful to the end user, we will probably end up with something just a little bit closer to perfect tracking than LibreOffice Writer, but I don't think there will be perfect tracking anytime soon. But I'd be interested in opinions on this.