This image meets the challenge, it's properly exposed without any glaring flaws. I think the main critique has already been made in the previous comments - it lacks a point of focus. The line of people almost form a leading line into the graduate in the foreground, but there's some much going on in the photo, the main subject gets lost.
I'm sure zooming in on just the graduate in the foreground would helped a lot. His expression is great and the other smiling people would have been enough to create the mood.
I like the concept. The photograph is a little bit busy however. At first glance my eyes aren't sure what to focus on, though I imagine the graduate in the foreground is your main subject.