Matchmaking really shouldn't be an issue. This is an unnecessary pain in the ass that has nothing to do with balancing or asymmetry. It's a core mechanic of the game and should function flawlessly. Don't let a match START COUNTING DOWN UNTIL TEAMS ARE 75% FULL TO CAPACITY AND EVEN. None of this counting down while people are loading in bullshit. Give us a full 90 seconds ONCE THE MATCH IS FULL (PLAYERS LOADED IN, NOT STILL LOADING) to pick our classes, sort out our squads, and figure out where we are going. QUALITY over quantity. Why the rush to hurry us into uneven, imbalanced teams? That results in the match often being decided in the opening 2 to 3 minutes of the match. Stop rushing us and stop catering to the Mountain Dew and Skittles crowd who need to always "go go go go". Give us a quality experience every single match via even teams and time for everyone to choose their loadouts and organize into squads. The 25 second timer should NOT START until EVERYONE IS FULLY LOADED IN. That 25 second timer should then be changed to 90 seconds so there's no rush. Let us pick our loadouts, form our squads, and organize a plan in a peaceful, relaxed environment. We dont need the stress! This should be a fun and enjoyable process pre game.
Also squads should fill up to a minimum of 8 before creating a new squad. Many 5 man squads is not ideal on maps with limited transports. Maybe this is a minor quibble based on the other issues being raised here but, I felt that it was worth mentioning.
I think the argument for default 5 man squads is a 5 man team at A B C and a roamer team to work as reinforcements.
I'd like it if they did what some other squad based shooters do. The first screen you see after the game loads is the squad screen, and from there you have to manually join or create a squad before you move on to the loadout screen. Just my 2 cents.
Full 10 man team is optimal due to transport limitations. If you on a map with 4 transports and you have 3 teams you use 3 transport to deploy and only have one left a if they get destroyed. If you consolidate in to 2 squads each unit has a spare transport. This is not to mention the maps that only have 2 transports. Really it's way more efficient to have squads maxed out from the start but, I put the limit at 8 for ease of switching squads.
The other solution to this is to create a game type that allows for smaller teams (like 10 players). This would allow for more matches, easily filled teams, and quicker matchmaking.