This is according to a recent interview with Kotaku in which they spoke to Overwatch’s director Jeff Kaplan who explained that it would be “complicated” to create such a system for Overwatch. According to Kaplan, he is aware of some of the proposals that the community has made, but none of them seem particularly satisfactory to him just yet.
He said, “There’s two versions the community has proposed, and neither is fully satisfactory to me. One is the honour system version where I queue up as a tank, but actually I want to play McCree, and the game lets me do that since Overwatch is very much about fluidly responding to the enemy team’s composition. The other version is that it locks you in. I think that also hurts the spirit of the game.”
He also points out how the current system used in World of Warcraft has its pitfalls, where tanks and heals get grouped up pretty fast, while those queuing for damage roles end up waiting 30 minutes, which is a problem he wants to avoid.