One suggestion that could potentially reduce congestion for AA/DM II battlefields is to remove the requirement of completing all 5 AA battlefields before getting access to DM II. Getting an alliance worth of people with DM II access can be challenging, and forcing each person to get 5 wins in a smaller group just puts more pressure and congestion on the 3 instances. If the bar to access to DM II is lowered, then perhaps more larger groups will try this, and instead of 1-6 people using an instance, ~18 people will do so more often, potentially cutting congestion by one third. One of the good things about delve is that there are no artificial prerequisites other than the leader having the appropriate key item.