This website is far past the point where having ranked and unranked games in main lobby makes sense.
Both sandbox and main lobby suffer from this weird choice. Unranked games should go in sandbox, which will boost the ever slowing population of 12 person closed setups, and ranked games should go in main lobby.
Without the influx of unranked games being made, competitive games will not be second paged so fast, and thus fill more often, allowing more than 2 setups to be played each round.