Lower the amount of options people can search in the match composer. With the amount of current options it makes it hard majority of the time to find a game in anything unless its peak time in the day. I think there are currently 140+ different options you can search which is way too many. You're spreading an already thin population even thinner. So here are all the options I think that should exist to better the matchmaking experience for search times.
1v1 (Slayer Only)
2v2 (Slayer Only) - TURN OFF FULL TEAM MATCHING
4v4 Precision Slayer, Objective, Snipers, SWAT
Mix Flag & Bomb options with Zone Control & Asset Denial an call it Objective.
8 Player (FFA) (Slayer Only)
8v8 Precision Slayer, Objective
Add Heavies to Precision Slayer.
Objective in BTB should be Multi Flag, 1 Flag, Neutral Bomb, 1 Bomb and Territories.
Make Action Sack a rotational 4v4 playlist
Make Infection a rotational playlist
Add party prioritization in the match composer. If you're searching in a party / team ONLY the first 10 seconds of the search it looks for a party / team of similar size and if it can't in that 10 second time period of searching you'll match anyone.