First off people shouldn't be allowed to team up with the same people twice in a row solo que. This helps stop syncers which is a small problem
Second they need to enforce role balance between teams. If one team has 1 tank,the other team should get one tank, melee, healer etc. To at least TRY to bridge the chances each team has, nothing worse when the enemy has a WAR and WHM together which is a fit wombo combo to trash you with CC.