I think there should be some type of map rating system. Then, you can organize the lobby by best rated (and most visited). That way, good maps will be noticed, and bad maps will not be at the top.
It would be extremely nice if you could have a way to have certain keys only affect blocks. That way, green keys wouldn't affect all of the green gates and doors in the map.
You should make a game where you could make your own map. It can be as huge as you want, and you can add vines, and lava, and upgrades like the parachute. That would be completely epic! Give this a good rating so the creator will see it!