@Toby
Having just done a test for the avatar idea, I tend to agree.
One of my favorite forums uses three columns at the top, with different purposes. The last so many posts, the most popular posts, and blog posts. It works really well, but isn't putting as much information per line as these are. I think the first column scans really well, myself, as it compacts the information into a smaller space, pushing the contextual information closer to its source.
Now, the second does feel a little harder to scan. So, maybe the first column is simply shrunk down on every device, and on the desktop you could either center it, or add some other information, or images to the right? I like the rows being closer together.
That might be a good place to put the add-on's stuff, and keep the info closer together. I was just envisioning a plugin that simply shows an Avatar of the most active users in a thread, and that might read better at the end of the line.
Anyway, thanks for working on this, I just found it, and think it is looking quite good already.