I think no DPS or Sombra+no DPS comps become dominant again when Blizz remove role lock in OWL. Tank/supps synergies are just too strong in this game, especially when two teams have about the same skill level. DPS are only good if you or your team is vastly superior than the enemy team.
Also, people don’t like playing tanks and it often leads to the opposite extreme way from OWL in competitive games : no tanks comps.
Ofc those things can be fixed, but it would touch the fundamentals, meaning they should build a new game from the ground.