In all honesty I heard about the map contest but I didn’t have friends willing to test maps. My friends and I rarely play and when we do we go 3v3 automatch, not testing maps.
I appreciate your honesty and I like your idea of getting something together that is more formal.
Taking time to test a map that may not get into the game is a waste of time. So I totally get people not doing it. Personally, I do not have a position in the community to do something like a formal test phase.
But testing a map right now should be fun for everyone. You get to try out some crazy new strat with commanders and there is no pressure. But people are afraid to look bad, lose, etc. But all you need is about 15 minutes of decent play to figure out most of the map.
Realistically you need two phases.
PHASE 1: Everyone tries the map out and we flesh out any major bugs, see where fights take place, see if there is some strat that can be abused, etc.
PHASE 2: You need top level players to test the map for balance, abuses, etc. But in team games, even this may not tell you much. Too many other variables.