"online matchmaking system". Found the problem. Just give people a server browser ffs.
This entire draw of Halo for a large amount of people is competitive ranked based matchmaking. A significant contributor to the decline in Halo popularity over the last few games has been a lack of any meaningful ranked matchmaking.
In a competitive game like Halo, not everyone wants to just play rewardless games against random people with greatly different skill levels. Even for casual players who don't care about ranking, matchmaking is important. When you have a group of your 3 other friends you want to play with, you can hop into matchmaking and ideally find a quick match vs 4 other players. You don't have to find lobbies that are "4/8 players", you don't have to worry about the server running game types you don't want, you just press play and go.
Currently the MCC has countless absurd issues. Lets say you queue up for 4v4 with 3 other friends. You often randomly have your group of friends split up between teams. Often times there are more than 2 teams. Sometimes you will get 2 People on Red, 2 on Blue, and 5 people without a team in a 4v4 playlist. Often times 1 player will get the ability to boot anyone from the game (in ranked playlists). They can't even get the spelling of 1st, 2nd and 3rd correct. I've finished in both 1th and 3st place on multiple occasions. It can also take hours just to get into 1 bugged out game with random teams and you get booted 1 minute in by someone.
343 really dropped the ball with this release. At least campaign works decently...