Several community members and internal staff have mentioned that increased levels of granular reading experience customization would be beneficial.

This is also well supported in the research.

I am imagining a 3-level progressive disclosure pattern for customizing your reading experience:

1. Defaults
2. Off-the-shelf "recipes" which is what we've built for Minerva and Vector this quarter
3. "Advanced" customization along the lines of what folks were able to do with the prototyping tool we built.