I’ve played 10 games in “QPC”. I’ve had ZERO with more than one player on a non DPS role, unless I also played tank, in which case we sometimes got a second healer, but mostly not. Please don’t try to sell me 
and claim it’s a pile of gold, I can smell it from here.
- Sentiments from people on the forums. Even with the fact that vocal minority phenomenons are common on all game forums (basically, someone who’s happy with the game has much less incentive to come to the forums compared to someone’s who’s dissatisfied and needs a platform to complain on), you can just go from post to post and compare the number of likes on posts in support or opposition to role queue and you’ll see that supporters far outnumber the detractors.
- Response from people on other websites where OW players congregate. Go to the twitter post announcing role queue, and you’ll see 100 replies praising rolequeue to every post complaining about it. Go to the youtube video announcing rolequeue and you’ll see a 95% like to dislike ratio. Go to the comments section and you’ll see that there’s not a single negative comment among the most popular comments.
- Sentiments from streamers/pro players. It’s very hard to find any that aren’t in favor of rolequeue.
- Just personal experience. I’ve talked with dozens of players on my friends’ list about rolequeue and only one of them was vehemently against it, while the rest were ranging from neutral to positive.
Now, none of those are conclusive evidence, but they are pretty damn good circumstantial evidence, and contrary to what movies would have you believe, circumstantial evidence is actually admissible in court, so it’ll have to be good enough for you too. 
Now what kind of evidence do you have to disprove this claim?
Yes, they have. You’re just spreading misinformation at this point.
Granted, that’s not a binding legal contract, but it’s about as firm as anything they ever give us unless it’s a feature already in development.
I do, it splits up the playerbase and makes matchmaking worse.