Atleast you have a guranteed 2/2/2 composition in Role Queue, in Open Queue you will most likely have 4+ DPS Heroes, 0-1 Healer and 0-1 Tanks, terrible experience.
Open Queue should only be available in the Top Ranks or Pro League only, since the ladder just doesn’t work in open queue.
Also you can easily see that the vast majority prefers Role Queue, by looking at the playercount/queue times.
With the diminished player base of open queue, people are in ranks they would otherwise not be in if the real competitors were still actively participating in the game mode.
This is the the reason why I’ve never played open queue and likely never will. I think role queue was necessary addition to the game but let’s not be like calculus and pretend that the match quality of role queue is so great when it is still quite trash due to poor matchmaking and other issues.