More on the general feedback side of things,
MCC Rumble Pit functions more like a Lone Wolves kind of playlist, Much Like Halo 3’s Lone Wolves or the short period when Halo Reach had an FFA Arena playlist where the max party size is 1. And while it does work well (especially following the most recent patch 3/3), it is rather disconcerting that it’s not a Rumble pit that’ll let me bring a party larger than 1 into it.
My suggestion would be to make a proper Lone Wolves playlist (and make it ranked, when that happens) and make a Rumble Pit playlist much akin to rumble pit in Halo 3, Reach, 4, etc. where you can bring your friends and have some fun in matchmaking.