Good idea, but when you focus on personality, by showing faces, then show the subject and reason to take the "workshop".
Also make signing up easier, by allowing one to try it out, before joining in. Maybe with a "simulated partner", that would be novel. Nobody offers simulated partners. You could use code-metric tools and nlp to make the simulated partner useful. However concentrate on the main idea: let people in, as easy as possible. Make them actively seek the signup button, instead of showing it into the face, without convincing arguments.
Please follow these guidelines: http://www.goodui.org/