For nightfall, 32 prison of elders and both raids on normal and daily heroic missions. Edit 1: these were my core ideas, you could add matchmaking for 34, 35 prison of elders and hard mode raids. It will be a bit harder with a lack of communication, so the matchmaking should include filters for specific searches. Even no matchmaking would be fine if they had an In- game form of an lfg site which was more effective.