I think that with all the craziness with watch faces (browsing watch faces is almost replacing my morning read...) An option to mark watch face as favorite is quite a must. Simple star to mark watch face as favorite and present all favorite watch faces in a third tab, so main screen will show: Home | My Watches | Favorites
Hope you'll agree with me (Another small features to complete the idea is an option to add custom tags to downloaded watch faces and the ability to filter by those tags, for example: brand name, color, shape, author..)