Superb plugin this is, and the code is written very professionally.
I noticed though that the plugin is missing the Collection's support.
Looking through the Flickr's API, I guessed that it'd be trivial for the Author to add the Collections - after all, they have just 2 API calls:
flickr.collections.getTree - to get a PHP, JSON, or XML list of all Collections with members-Sets.
flickr.collections.getInfo - similar to flickr.photosets.getInfo
Looking at how much effort the Author put into this plugin, I trend to believe, that it'd be much easier for him to add the Collections support, rather than anybody else to write up the alternative plugin, with full Flickr API framework, with caching, and from ground up.
However, I do need Collections badly now, as it seems that Flickr is not offering Galleries anymore (or its superbly non-intuitive UI is hiding them all too well).