6v6 should not come back.
6v6 had a higher team-execution ceiling, but few people ever actually used it. Individual mechanics shine brighter than ever before in 5v5 and every player can make a difference without waiting for someone else to do their job first.
To me, this is the essence of what makes an FPS game great. At the same time, we haven’t lost the playstyle options, teamfighting, and resource management that make OW unique.