I understand why they have the Crucible playlists set up the way they do currently. Its to prevent certain gametypes from having low/empty lobbies, so the small handful of people who would be play, say, Supremacy, actually have a fair chance of playing Supremacy without waiting 10 minutes to potentially not find a match. I do wish there was some sort of voting system in place, similar to Halo 3 for example. The maps don't feel empty to me, they're scaled to accommodate 4v4 after all. Though, some are large enough that it seems like 6v6 might have been a thing on their mind at some point and decided to change it. Who knows.