My solution would be dynamic server browser. Sync servers and gather same skillset people together. If people are playing with friends/team, they should stay in same server and try to get them on same side. Steal some pro players from other servers and ditch the random in next server after unbalanced match. If game is balanced, there is no need for this to happen.
Hide levels/names or fake them to test morale boost. Do this for scientific purpose. I believe there is tremendous impact. Create fake nemesis people that appear haunting them, so they have personal reasons to fight their best. This is called player engagement.
But why I chose “Post-Match Shuffle: Allowing you to create a team composition, but with poorer match balance”
Team composition is important, especially when playing with friends. People can still fake their skills playing intentionally bad or simply just trying something new. Actual problem is that there is no borders on serious/casual gaming. Not enough good stuff to motivate people playing their best sides. Especially if you have everything you want (pointing at you high levels, its your fault)
When playing casual, it should not matter who wins anyway. People are just having fun together in nice game where everyone is smiling doing some trickjumping or knife battles. Living happily ever after.
When playing serious, team composition and merc choices become important. It should not matter who wins anyway, because this is competition now. Only best teams/players wins, there is no balance for that. Sure you can play sometimes easier players, but hard players are going to play hard. They are going to use their own voice-chat. Keep selecting best merc combo synergy. Reporting enemy movement. Planning tactics. You cant beat that alone, unless you learn from them and possibly learn faster.
So we get to point what is actually important and what is balance.
Is balance that you get 50/50 win/lose ratio? I dont think so. It does not encourage you to play your best, since you will anyway win 50%.
Balance should be more like 90/10 win/lose ratio for best player. Now balance in Dirty Bomb feels like 60/40 ratio, thus not giving enough encourage for playing your best.