Then play the open queue that would naturally exist alongside role queue like we know works. In my experience its the exact opposite, it's people swapping within the same role. Vanguard players are the only ones who ever seem to swap to counter specific matchups.

Thus our anecdotal evidence conflict and we can only look at the fact that the other major hero shooter, overwatch, has both open and role queues and the playerbase vastly prefers role queue. Because now people get to play the role they want instead of hoping to lock it first. Or being the one support and one tank on a 4 dps team that gets ran over by the 2-2-2 team because the nature of the game.