Originally Posted by
Frozen Death Knight
Not true. If you queue up as Alarak in QM you get matched against Sonya, who is a Warrior, or vice versa. The same happens if you queue as either Abathur or Tyrande. Quick Match rules generally try to match roles based on Warrior, Assassin, Support, and Specialist, but there are pools of Heroes where the matchmaker thinks you should be matched against each other despite them not having the same role label.
Blizzard frankly needs to rework the labels entirely, since their current iterations are extremely broad and non-specific. Plus, certain Heroes synergize very well with each other while others make zero sense when on the same team, and this is without even partying up with people. Certain Heroes can be almost completely unplayable depending on both the map and team comps, which is why you get so many Tracers, Genjis, Novas, etc. that become pure pub stompers since the random nature of QM doesn't give you enough tools to combat them.