Exactly. Some players get angry over a game, and then perform worse. Personally, I don't understand the feeling of anger, only frustration, and the concept is strange to me.
What this game needs is to prevent two users from playing each other more than once or twice in a given amount of time, because otherwise they'll keep meeting and one will keep reaping rating from the other until they are far enough away in rating that hopefully someone pops up before the other player can match up with them again.
Why not a siege war where it starts normally but the troops can't attack until the times up. After the times up the units will be clashing and the survivors are allowed to garrison their unit. It last until 5 rounds and it become normal which the players can control where to attack and defend. This can prevent from miner city and massing.
Well then everyone will just mass shadowrath and make a magikill, destroy albowtross with poison spray and electric wall and then poison and wreck everything else with the shadows.