One of biggest issues right now is team balance and endless stacked matches. Team selection currently appears to be completely random with the rule that if numbers are odd attackers get the extra player.
Here is a suggestion for how balance could work considering the stats that Echo could be or is giving us. I would base the balance on the following:
k/d ratio. This is pretty obvious but on the whole players with the highest k/d ratio tend to win maps in DB in combination (one single player rarely makes a difference).
XP earned per match. Players with the highest XP at the end of the match tend to be doing the objective / playing their class as well as fragging. They are more likely to play as a team rather than individuals (this game really doesn’t reward going it alone - a top rambo player may end up with a 3-1 k/d but did nothing for the objective and still lose the match. An entire team with a 3-1 k/d is clearly containing the enemy so will almost certainly win).
Win/loss ratio. This speaks for itself and I think is the most important factor. Certain players combined will overpower the other team 90% of the time. It usually only takes 2 or 3 to do this.
I would suggest giving every player a rating based on the above three figures. The figures should take into account other players in the match. (for example if player X and Y have won together say 70% of the time, ensure they are on opposite teams, assuming that the next highest combination of two players together is less than this by a certain margin say 10%). In terms of working out balance I would say ‘X + Y together win 70%’ is better than ‘X wins 80%’ and ‘Y wins 50%’ say.
There is also player level, but I don’t consider this represents a player’s skill as much as their persistence.
Most of the top players are willing to swap to even up but can’t due to the quirks in the lobby (e.g. the ‘Join’ button to swap teams gets locked out once the lock in starts, but prior to that you can swap from a 5v5 to make a 6v4…). You also can’t join any team if you were in spec mode the previous match.