I think the only thing that would get me to resub Gold at this point is if they went back and took out equipment in 3's matchmaking and also made the map packs free so as to give some incentive for some cheapasses to go back to it and populate some of the lists.
I doubt they will make the map pack free, but at the very least they should make it so that there are no DLC restrictions on playlists. They should give DLC a high priority weighting to balance this, so that if you do get 8 people with the DLC there is a good chance you will get a DLC map. That way more people will be able to populate the playlists, and DLC owners will still get DLC games when they match up against other DLC owners. Remove Team Mythic and either replace it with a playlist which contains all DLC maps or at this stage just don't bother with a DLC playlist.
Actually I think I want to see them go in and really change up Halo 3 matchmaking, it is left in a terrible state. Rumble Pit and 7 on the 7th should be merged into one playlist. Reset the exp every month for the achievement but don't split the player pool. Put stuff like infection, KoTH, Odball in there. Lone Wolves should be slayer only. That would be great for the ranked/ social divide.
Clean up Social Slayer - make it 4v4, with the low population size and quitters less players is better - it should be Slayer only but keep the other settings the same. I.e. a mix between AR and BR starts. Ranked Team Slayer should be BR starts all the time. Again the ranked/ social divide is still important and there is a strong distinction between them.
Remove Rockets, Swords, Hammers etc from all playlists and shove them into a team action sack playlist - shove things like Grifball in there too - have it as a catch all playlist for any team based fringe gametypes.
I doubt think one would go down well, but condense Snipes, Swat and MLG into a Team Tactical playlist.
Playlists:
Ranked:
Lone Wolves
Slayer
Doubles
Tactical
Social:
Rumble Pit
Social Slayer
Multi Team
Team Action Sack
BTB
I think that could work fairly well? 4 ranked playlists and 5 social playlists is less than we have now and there is still a large degree of player choice.