I would've thought the same thing. But I emailed Angela highlighting some of the specific things I've done since being waitlisted last year (like retaking courses, employment history), and asked for advice around putting together a more competitive application for next year. I highlighted my continued interest in the program, and she referred me to Terry Gardiner to speak further about the questions I had. Apparently he's the person to speak to if you are looking for more specific advice, especially if you're considering applying again.
I definitely wouldn't go overboard with emailing them, but continued correspondence over the next few weeks couldn't hurt!