Here's a couple of ideas that I think would work pretty well and would help out quite a bit with functionality:
First, since there's a lot of digital downloads being sold as well as digital versions of movies, I think it would be a good idea to have an option to somewhere display the total space taken up by the video files of the catalog as well as the total files. That should actually be a rather easy thing done as it would only require determining where to put the display at and some mathematical inputs for the totals. If you wonder what I mean, look at Anime List Builder. When you are cataloging your anime collection it will display the total size of your collection as far as the video files go.
Second, one of the things which it seems logical to be there is the ability to work with the various episodes information from within the main series "page" for lack of a better word. What I mean is that somehow, the episodes should be tied to the main series infocard so that you can work with the data. Another way of putting it is, you would click on the series name, then have a tab you could click which displayed the list of seasons/episodes along with other information you wanted listed like maybe length, size, date released, etc...
Oh, what about making it so the skins can use xhtml as opposed to just xml? That way it would make it easier for manipulation of the data for display.
Just some ideas.
- KatLeeH