PS...just rolling up my sleeves and taking HWD for a test drive and checking out all the settings and whathaveyous, so feel free to dismiss all my ideas as stupid and tell me these are dumb ideas.
I installed the sample data, then published a dozen videos, then went in to remove some of the extra categories and found myself having to check the frontend to determine which categories contain no videos...since didn't show in the backend.
Then I wanted to see what happens when you delete a category that had videos assigned and discovered that it changes the video's category field to 'select a category,' but found it after clicking each respective video.
I love all the settings/options/bells and whistles you have packed into this bad mamma jamma, too; well-done, guys...good stuff!