>>536263330
They explained this in the video you metal ranked moron.
there are unequal numbers of players queuing for each roles so the queue times either need to be astronomically high or the strictness of the matchmaking will have to be relaxed for the unpopular role, causing even more unbalanced matches. Neither outcomes are desirable. This is especially problematic at the higher ranks where there is a smaller pool of players to with. The current system is targeting fast queue times with reasonably fair matches. Role queue does the exact opposite so they will never implement it.