I would like to see a pause button for broadcasting. It would allow for quick changes on the fly without end users being able to see things as well as them needing to see the stream go down instead of just pausing.
It would also be nice to see a counter of how many people are connected. I know that you can see that in studio, but we use procaster exclusively for our broadcasts. There's room in the procaster window to the right of the counter, right above the CPU percentage.