1. Variable fonts
  2. What would be the best way to select and style some elements in a particular page. Something like @page :nth-child(67) {} or @page [data-page-number=67] {}
  3. What about an imposition hook / script (need to fill the book with blank pages) that could produce ready to print spreads.
  4. As the lib evolves quickly, what about a version number in dist/paged.polyfill.js first line?