I've been a Firefox user for over 17 years now and it's been my default browser for a long time. I've got a lot of bookmarks and I feel it's time Fx gave it a good revamp. I use the keyword feature a lot to quickly open website that I bookmark frequently use.
Currently I need to bookmark a site, then go to the Bookmark Manager, find the bookmark, then add the bookmark.
It would be great to be able to add the Keyword function in Bookmark this Page (Ctrl+D) dialog itself. Probably just under the 'tags', this would make it super easy for those using the feature.
Another feature that would make bookmarking more intuitive wold be the ability to search folders (or Bookmark Location), also while bookmarking.
Here's a mockup: