I think there's a place for the "filler" sometimes. In some instances it has been useful when the recipe writer puts in notes about substitutions, alternate methods that worked/didn't work, etc.
I think filtering by dietary requirements is gonna be pretty important. gluten free, vegan, diabetic, etc.
I think suggesting sides or accompaniments would be cool. Like a chocolate cake recipe might also have links to frostings and fillings. a steak recipe might have links to mashed potatoes, etc.
automatic volumetric to weight conversions.
I also like the idea of chaining recipes. I just made that up but the idea is that you can start with something like say blanched broccoli and it would link you to what you could do with that blanched broccoli like broccoli salad or adding it into a cream of broccoli soup. then you take the soup and make it into a casserole, etc.