It's probably already on the agenda, but a history feature would be great.
Not only that, but what I'd love to be able to do is bring up past single queue tweets and then sort them, listing the most re-tweeted content first. I can see this having a few benefits. There might be times when you have a RT that you like but aren't 100% sure you want it in your recurring queue. If we can see what (if any) reaction that tweet receives that could help decide if we want in in the recurring queue. In other cases, one might want to test the wording on a new tweet before deciding to add it to our recurring queue.
Having an option to then "move to recurring queue" from this history would be awesome.