I like Role Queue. Single-tank was poorly thought out, I agree.

Fundamentally, I think OW copied some things from TF2 without understanding how they interact with lower playercounts. They copied TF2's long rollouts and respawn timers, but didn't realize that this makes death way too costly in a small-team game. In 5v5 at a good level, a single kill can basically end the teamfight. If they want to drop playercount, they need to find a way to fix that. Imho that's why so many of their "Arcade" modes play with alternate respawning mechanics, like freezetag or the silly "StarWatch" thing.

Also they wanted big flashy ults without thinking how that interacts with the rest of the game. There's a reason that most competitive twitch-FPS games don't have nukes on the serious maps.

Imho, if I were running OW2?

1. For competitive: 4v4. 1 heal, 2dps, 1 tank. All healers share some kind of special rapid-respawn passive, like they can respawn at the Tank or something. Make up for it by reworking more DPS classes into having off-heal powers like Sombra and Soldier. Remove the rapid-respawn passive in open-queue-style games.

2. Nerf the ults in general. Either slower build or just lower-power. Although if you go slower-build, you need to come up with a sane way to have the charge carry between rounds, which would be tricky to get right.

3. For casual: 8v8. Double the 4v4. 4dps 2tank 2heal. There's a reason TF2 played 12v12 casually and 6v6 competitively. If you're farting around trying things out, you don't want to be the lynchpin of your team.

Then the number of heroes and the popularity of the roles reflects the number in play - there are twice as many DPS heroes to choose from, twice as many DPS players, and twice as many on the team.