There should be an extra form for adding feeds only and an option to choose a category while adding. Then I wouldn't have to save all feeds twice.
Also it sometimes takes about 10-15 seconds to load a page with lists of RSS feeds (I have approximately 50 feeds saved). Isn't there a way to make the process faster (e.g. not retrieving updates from all feeds at once but only refreshing small groups of feeds before the main cache is deleted)?