A kindly recap on how things work here:
Work is done on a voluntary basis.
Maintainers don't want to work on features they don't care about.
Contributors usually contribute code that fits their own needs.
Maintainers do welcome all kind of crazy feature requests on the form of code patches. They decide if the patch is good enough and/or fits in the scope of the app.
For all kind of "out-of-scope" features there's
https://github.com/koreader/contrib.
The best way to get an enhancement is to submit a patch against the main repo and gather feedback. Worst case scenario: not accepted upstream but you can still use it as a standalone plugin.