I am loving this plugin! I've really been able to tweak it to do exactly what I want, and appreciate its simplicity and flexibility. I'm still testing a couple others, just because I like to stay abreast of available options and enjoy seeing who's doing what and how things evolve.
But enough preamble, I have a new idea and problematic: language management. What if a network's sites exist in multiple languages (which mine will soon)? I would only want the feed to appear in the appropriate language.
As your plugin is set up now, the easiest way to go about this would seem to be to allow for multiple feeds. That way each could represent a language, and each feed could be added to as sites were translated, or excluded sites as needed (I really like this aspect of your plugin, adding individual sites rather than having all by default then excluding). They could then be called by shortcode or PHP with id=1, id=2 etc.
What do you think?!?
Just for info, I use WPML for language management. Don't think that really matters, but I know they promote plugins that are compatible with theirs...