The playlist system seems to be pretty unsustainable (especially with the lower population) so I think 343 should work on creating a match composer for social matchmaking in Infinite similar to the system in Halo MCC. Here is how I would have it setup:
Team Size: 8 Player FFA, 2v2, 4v4, 8v8, 24 Player.
Modes:
8 Player FFA: Slayer, HCS Slayer, Vampireball, Snipers, Fiesta, Action Sack, Escalation Slayer, One in the Chamber.
2v2: Slayer, Oddball, CTF, Dodgeball, Snipers, Fiesta, Action Sack.
4v4: Slayer, Arena, Attrition, Fiesta, Snipers, Action Sack, Tactical Slayer
8v8: Slayer, Arena, Fiesta, Snipers, Action Sack.
24 Player: Team Slayer (12v12), Team Arena (BTB), Team Fiesta, Team Snipers, Last Spartan Standing, Infection, FFA Fiesta, Escalation Slayer, Action Sack.
Slayer - Social Settings (AR/Sidekick)
HCS Slayer - HCS Settings
Action Sack - Kong Slayer, Ninja Slayer, Rockets and Repulsors, etc.
Snipers - S7s Only
Arena - Oddball, Strongholds, King of the Hill, Capture the Flag
Escalation Slayer - FFA Gun Game
Team Arena (BTB) - Total Control, Stockpile, Capture the Flag.
One in the Chamber - Tactical Slayer settings. Spawn/Respawn with one bullet. Kills generate a bullet.
Also separate from the Match Composer there could be a weekly Forge Highlights playlist curated by 343 to showcase some of the best forge creations of the week.