For months, the Arena community has wondered if there was a hidden Matchmaker Rating (MMR) in Arena that pairs not only players on similar scores, but also players of similar skill. Lead Game Designer, Ben Brode, joined Hafu on her stream to clear up the matter once and for all. He was also asked about some other smaller things.
The key point made, was that Matchmaking only looks at win-loss records when pairing players in Arena. The only exception is made for "brand new players", who are treated as if they have one more loss than they actually have, and will be matched with other new players if possible. The exact numbers are still being tweaked, but this lasts for your first "two or three runs" on a new account.When asked about the possibilty of an Arena leaderboard, Brode was tentatively positive. It's something that he would like to see, but he did have some concerns about how to run it. He mentioned they can't do it retroactively, as players may have retired runs that they would otherwise have tried to do well in, and so such a leaderboard might be monthly. He also seemed to imply that no framework was in place for a leaderboard at this time.Hafu mentioned that card rarity causes balance issues. She explained that she understands that common cards are generally more simple, but she feels that certain cards being common causes balance issues. Brode replied that the design team actually do factor in rarity for Arena quite heavily during the design process. Brode concluded the interview by saying that he would love to have more control over Arena balance. He said they were working on giving themselves more tools to help with that, and that he was hoping to experiment more with Arena in the future. He brought up the possibility of weekly meta changes with different cards being more available during some weeks.
The MMR answer is an interesting one. The reason rumours about it come about because some players seem to get significantly easier opponents than others on a regular basis. One theory for this, that now seems more likely, is that games are easier during prime time on the region where you are playing. This would make sense, as people who play all day, during working hours, are more likely to be strong players. It is also possible that it is simply confirmation bias at work.