This is an idea to make it so you can collapse Category, Theme, and Type when you click on the titles and also to have more collapsible/expandable links that show more sprite/sound library collections. In my example, what would normally be the current splash collection when a user opens the library to use a library sprite in a project would show the selected library collection as bolded and expanded text like it does now (bolded "all" text) but the other collections in Category and Type would be collapsed unless clicked and Theme would remain collapsed unless clicked except for a small number of themes about current and upcoming holidays and events. I didn't include any example of that, but when Theme is clicked it could still show stuff like "Castle, City, Music and Dance" and etc. The two "search for" sections wouldn't expand anything, just let you type in a library or sprite to search for. These could be consolidated into one search bar and advanced features that show or pop up could address whether to search for libraries and/or sprites. This would probably have to involve some kind of way to import project sprites into a different library system that would need moderation/facilitation and a chunk of technical resources.
used screenshot of using scratch library for a new sprite in Scratch online mode 5/12/14, left is screenshot and right is modified image trying to explain my idea if theres already something like this (e.g., i just haven't found the feature or modifications are already out there) please let me know!