The community-made map included in the Heavy update is cp_steel, by Jamie 'Fishbus' Manson. After the Pyro update we received a lot of email telling us how wrong we were in our choices, and cp_steel was an easy next choice due to the way it dominated the suggestions. If you're firing up your email right now to tell us that we never get anything right, please include suggestions of what map(s) we should be looking at next.