Starting with Season 9, legendary players will no longer be able to duo queue. Because we have so few legendary players, it’s very difficult to get legendary players into an appropriate match. When legendary players duo queue, it greatly compounds this difficulty. Our goal with this is to improve matchmaking at higher skill levels.
Why didn’t we restrict duo queue all-together? We didn’t want to remove this option for everyone, when the problem we are trying to solve exists within a tiny fraction of the player base.
We’ll be keeping a sharp eye on how this affects Season 9. This will be a fairly easy thing for us to adjust if we feel it necessary in the future.