I hope it will be more a hero queue thing then a role queue.
Since for having a working role queue you first need to make players make to switch to main a tank or a healer instead of staying main dps.
And that would be really challenging. And would take some time.
Yes like that. A flex player would select all of them.
But with a restriction:
You can only select heroes in a certain range (like 1000 SR)
So for example you first pick hanzo, on which you have a hero SR of 2400
Then you try to select widow where you have a hero SR of 1250. You will get the message this hero is to low level
So you select mccree who is 1998 SR.
After that you select lucio who 3001 SR and get the message he is to high(to high to select together with mccree)
This way you build up your hero pool.
(With this a troller/tilted person etc can not select a hero he is bad at (or think he is good enough with, but isnt) So a junkrat main of a hero SR of 4390 can not switch to a widow he has only a hero SR of 2200 with and destroys the game for the rest)
Then the matchmaker groups you with 5 other players who have only heroes within your min-max range. (without like 2 players who can only play hero X) And it tries to have at least to have a balanced team with a main, off tank/healer and 2 different dps. But only for like 1 minute. If not he just will group you with 5 other players.
But the opponent will always have the same hero pool.
So if the other team has a very good widow (or rein or other hero that can only be countered with mirroring it) . You will always have at least one player that can too play that hero on the same level.
If the enemy has a reaper and you got no counters. It will mean you also have a reaper and the enemy has no counter heroes.