I htink endnote would benefit form having a list of PDF annotations and highlighted text visible in the preview pane of the library and in the PDF viewer pane. Mendeley has a list of notes and Sente, when it was operational, had both notes and highlighted text, all visible from the main screen. That provided an incredibly useful overview of the relevant and important points which I could browse through as I browsed through the whole library. I really miss that from Sente and was surprised that no other reference managers decided to include a similar feature.