Anyone creating an OSS collaborative authoring platform could benefit from lessons learned in commercial authoring platforms:

http://blog.inkling.com/2014/06/problem-of-structured-author...

http://alistapart.com/column/wysiwtf

We need momentum around one integrated OSS toolchain, including illustration (Inkscape) and CMYK color for printing (Scribus). This would help editors and publishers who want to move away from rental pricing for authoring software.

As anyone who has tried to find good books in a sea of free books knows, there isn't a standardized way of collaboratively improving book Metadata. This needs to include e-production history, translators, print publication history and content objects _within_ books, viz. Doug Engelbart's purple numbers, http://www.dougengelbart.org/about/ohs.html