Since people are always editing the files to manually install a theme, changing it to make it just right, I think there should be a file editor/ftp client in the admin panel. This way people don't have to run an ftp client everytime they want to make a simple change when they are already in the admin panel.
Does anyone else like this idea?
You can edit the theme files for non-default themes in the admin panel. go to 'Themes and Layout', then click on 'Modify Themes', then select your theme of choice.