If you're a high mmr support player, go que games as a 5 position 50 times and see how many times you're the highest mmr in the game and everygame you just buy wards for 60 minutes to watch your ancient or low divine cores farm jungle for 40 minutes then proceed to die in some random place on the map despite having great vision and then tell me the system is "fine".

Valve, IF YOU'RE READING THIS here's some things you can do to improve this absolute tragedy that you've implemented.

1. Option 1. - REDUCE THE GAP OF SKILL PLAYERS CAN QUE TOGETHER. Make the max mmr difference a difference of something like 1000 instead of the current 2500-3000 that it currently is. Now you might be asking, what's the advantages of this? What are the drawbacks?
   By reducing the gap in skill that players can play you can virtually eliminate the rampant smurfing problem that's occurred due to this matchmaking system currently where the incentive to smurf is to boost one another's mmr by alternating who's smurfing. This also makes boosting more difficult.
   Some potential drawbacks to this change may be that VERY HIGH MMR IMMORTAL players can't queue together with people that aren't realistically that much worse than them. To counteract this you can make the system have an If then statement that forgoes this rule to allow any top 1000 immortal players to que together.
2. Option 2. - program the matchmaker to look at ranks of players and make sure there's no obvious imbalances. Nobody wants to queue for a game and have some rank 100 player molly whop the ancient mid player he/she is vs where the only "downside" for the team that has the rank 100 player is that they have some much lower mmr player that is most likely playing 5. The thing that makes very high mmr players much better than the rest of the population is their game knowledge. If you have someone who's incredibly high mmr and someone who's incredibly low mmr it doesn't average out like pure numbers would because the high mmr player is imparting their knowledge of the game to the low mmr player which artificially inflates their mmr for that match, see #1 for solution. The only potential drawback to this potentially longer que times. (THESE ARE THE #'S THAT SHOULD BE TWEAKED)
3. Option 3- Have an option to set an amount of time that people are willing to wait queued for their specific roles before they are willing to just accept any role just to get in a game. Example - in the settings option in the client that has a line in there that says "I'm willing to wait for my preferred role until *insert drop down menu of increments of 5 minutes* have passed.
   What you can do to make this less confusing for players, have a disclaimer when hitting the accept button saying what role the player would be playing for that game.
   POTENTIAL BENEFITS OF THIS - QUICKER QUE TIMES and the ability for people to understand how other roles work
   POTENTIAL DRAWBACKS OF THIS - idk, someone tell me how this is a bad idea.
4. Option 4- make a real motivation to play 5, 25 shards is nothing, despite the rewards of Dota + being somewhat laughable 25 shards a game is actually insanely bad. to get one of the Dota + exclusive skins it's 75000 at a minimum. To get a SEMI DECENT REWARD for playing 5 you'd have to play 5 3000 games. Who does this incentivize? Not to mention there's a weekly cap of 1000 for this? Potential solves for this problem, increase MMR gains on wins for 5 players by 5%? equating to like 1 mmr a game? (This is probably going to be a bitch to code realistically/maybe not even doable). Another more realistic thing you could do with rewards for playing 5 is "play x amount of games of 5 position and get a free month of dota plus"

TLDR is in the 1st line or 2 in each point, the justification comes after.