Hi there,
I’d love if there was a word-processing feature integrated with the pdf reader that allows you to take long-form notes with formatting tools (like google docs) but connected to each pdf. I prefer to take notes that way (outlining) over directly commenting on the pdf. These notes could then be exported to build an easy annotated bibliography. I primarily use Mendeley because they have a box for general notes in their desktop app, but would definitely switch to Paperpile if this feature was added.