Currently you did improve just the printRSSHeaderLink, which is not enough I think. What about the other ones who generate clickable links, like printRSSLink or printAllTagsAs? They should also get a nofollow attribute. It makes no sense that search engines follow those links, because all that content exists somewhere in their different albums, subalbums... Users (usually) not interested to find their RSS Feed, archive or tag cloud within the SERPS. This definitely leads to duplicate content. Maybe you could add an option, where the user can decide how to handle it, with or without a nofollow.
Regards,
Steffen