Thanks Kris for these good ideas, and good to know that someone was listening during the webinar :-)
Just wanted to let you know that your first idea is already implemented for version 5.4 - both metadata and TOC panels can be resized to leave more room to the viewer. We've also added a "full screen" icon, which will open the file viewer in full screen as a lightbox.
Not sure we fully understand the purpose of a retention policy that doesn't actually delete the content. But in any case, we believe that this functionality can be achieved today (though in the opposite way) by using the "IEs to be deleted" report which list IEs scheduled for deletion in a given timeframe due to Retention Policy. Users can run this report periodically and decide to modify the policy for IEs that do not require retention.
When searching in Primo for a word or phrase, that search term will pass through to the PDF viewer, where it will be highlighted without having to perform another search in the viewer.