I would also like the Halo website to have a place where people could vote for their favorite game type and map combinations to be in the playlists.
All the popular gametypes and maps would be in.
Also, the same as above for other gametypes, let the most popular and best forge-made maps be able to be put in the gametype's respective playlist. (For example, a great infection map would go in the living dead playlist.) (Although, this would really only work if Forge lets us have more colors and textures. Too much gray forge maps would ruin the experience.)
If you don't play the game a ton and haven't accumulated a steady group of online people who always want to play customs, then yes it can be. From what I remember of action sack, it really isn't that great of a playlist. A custom game matchmaking lobby would be great.