It'd be nice to be able to define which renewals are "seen" and which are "unseen." Maybe a syspref that lists the possible renewal methods and one checks a box for those that are to be considered "seen."

For one thing, this would give an easy place in Koha to see which are which. For another, the feature as it exists now makes some assumptions that won't hold true for every library. For example, not every sip-based renewal option requires one to have the item in-hand.