I still question how well such a system would work without a massive playerbase. Either the rules are flexible and people bitch every time they get something that doesn't match up, or the rules are rigid and you get people filtering down to one gametype on two maps with strict skill ranking complaining about how matchmaking times are suddenly huge.
Like, it's already hard enough to find matches in a few different playlists in MCC. If you implemented such a system on MCC you'd be stuck searching for even longer.
I understand the developers and your concern for wait times but factor in the following:
1. Quitting, dashboarding, team killing etc based on players not getting to play what they want. Toggles increase player retention in game providing an improved experience by keeping player numbers in games.
2. Skill matching parameters could be wider as players have more experience with maps/gametypes of their choice. This increases over time as well, players get better at what they practice or choose to play with their friends.
3. By default all toggles would be on e.g. all maps and all gametypes. Most players or casuals or first timers etc would never even alter the widest possible set of toggles, this is basically what matchmaking is now e.g. run by developer choice of maps/gametypes per playlist with weights on votes/veto variants. If matching times were slow players can simply have everything on, again player choice and immediate search parameters based on real time reactions to search times e.g. not waiting on developer actions.
4. The vote/veto variants presented are based on matches within toggles, this translates to developers not having to spend so much time on playlist selections and variants. The data is driven by player/party choice more so than incorrect developer assumptions or selections. How many maps in MCC have you really played? How many gametypes in MCC have you really played?
5. Minimum toggles required. Players would be forced to have a strict amount of maps or gametypes turned on e.g. you can't just toggle only one map and gametype on. This translates to keeping search times and player/playlist pools wide enough to be quick.
6. PC games with similar populations do just fine with server browsers. Toggles are a hybrid system taking the best of both server browser and developer based matchmaking systems.
7. At any time a player could choose all on quick search or match based on my toggles e.g. a toggle on/off for toggles. Simple and efficient.
8. Certain playlists could ignore toggles e.g. action sack. Playlists could also have minimum population thresholds and dynamically display if toggles are allowed or not e.g. population drops below 1,000 or 10,000 in a playlist and toggles are defaulted to off for fast games. When the population returns to that playlist toggles can be on again. Again a real time system.
9. Perhaps a minimum number of games are to be played before you can use toggles. Similar to Super Mario Maker unlocks.
10. No junk or unfinished/untested maps/settings like a server browser only system.
To me so much of why players don't stick with a game is gaining the experience to enjoy the game, getting to choose what you play and not having their experience ruined by others. Having toggles at launch of a Halo game hits all these key indicator points to retaining the largest population you can.
Take a small subsection of the community, say MLG/HCS. Pro and semi-pro players find a developer sanctioned map or setting to be great, they all will gravitate to toggling it on. Say they find the opposite so they gravitate to switching the bad ones off. Matchmaking automatically shape shifts and the vote/veto options help keep players coming back to play what they actually want to play. The developer didn't have to sustain anything, the systems are dynamic in nature and deliver in real time.
The thing I don't get is not trying this sort of system once in the life of Halo matchmaking. It's basically just queries/queue work around systems that have existed and iterated over the years. Why not layer this on top so it's all there at launch? Why not increase population by releasing multiplayer only on Windows 10 and allowing cross play with the X1? Just some ideas anyhow.