So the only thing that would incentivize you to make a good map is a silly medal and the feeling of superiority over the other people in the jam? It sounds more like an issue of not having your own standards for working rather than actually thinking having a contest is a "good idea". It's pretty selfish to only want the contest for *you* to be able to somehow "map better" with a reward that isn't even intended to provide anything other than a little medallion showing participation. Push yourself, don't let contests push you.
I'm not worried about winning a silly medal, I've taken part in all the of 72hrs. But having an incentive to push your self more is better, saying that it selfish is wrong. Having a reward for pushing yourself is what pushes a lot of people.
I like the idea of expanding out to all type of content, but it just gets messy and confusing. Most of these maps wont be tested again or touched again, only a few will. I know you are trying to expand this 72hr thing but I think it needs to be drawn back. I have only seen about 10-20 of the maps, I have no idea about that rest. And there is no easy way to see what was submitted.