I don’t think you’d even need to go that far, just make certain DPS massively punishing against barriers, like Soldier or Junkrat to the point where you’ll want to run other Tanks for things like Matrix and Barriers to deal with them.
Seems pointless to implement a restriction on team building comps when there’s so many DPS crying out to be relevant because Snipers/Flankers just outclass or counter them.