Your code modifications for http://wikitolearn.org/ are interesting. I'm pretty sure that KDE policies don't force you to fork MediaWiki extensions locally, so your patches are definitely welcome upstream.

I'm not sure what you mean with your point about <dmath> being rejected by the community; perhaps you refer to some performance decision made by WMF. If your modifications to Math are incompatible with some decision of the maintainers, you can ask a different repository on gerrit or another branch on the same repository, so that non-WMF users can use your code.

As for your comments on chapters and drafts, I don't see anything incompatible with how Wikibooks and Wikiversity work. If you have a solution for what we call "book management" i.e. https://phabricator.wikimedia.org/T17071 (worked on by Raylton and others with https://meta.wikimedia.org/wiki/Category:GSoC_Mediawiki_Book_Experience ), that's especially interesting.

To reach the Wikibooks and Wikiversity community, the best way is to use a medium that can involve their active editors, such as their mailing lists (cc'ed here) or wikis.

Nemo