Halo 2 classic has its dedicated playlist, as well as the team hardcore playlist. The regular playlist is geared toward casual play, while the hardcore playlist is geared to the ultra-competitive H2 crowd. H2A gets a regular, casual playlist, as well as a competitive one with the HCS settings.
H1 was given a population count of 2v2 because that is geared toward the the ultra-competitive H1 crowd asked for. But what about the casual H1 crowd? My proposal would be a second dedicated playlist, just like H2c gets, so that we can have a casual and a competitive playlist. Keep the competitive one at 2v2, and make the other one 4v4. I would love to start playing MCC again, but these playlists drive me away more than they give me incentive to keep playing.
There have been a lot of requests for H3 MLG settings as well, so I see little reason not to give that 2 playlists as well, and you might as well do H4 too. I would prioritize this toward H1 though because it is the only game-specific playlist where a team of 4 cannot search together.