I have about two dozen folders full of bookmarks, and some of them have sub-folders. When I go to bookmark a page, the dialog box is ridiculously small, for n apparent reason. If it started out much larger, or if I could resize it to the full height of my screen, it would be so much easier to use.

Also, it would be so much easier to provide feedback if you just had a "Suggestion Box" conspicuously located on your website.