More matchmaking transparency
Why? Because that would lead to griefing.
In the olden days rank was shown and it led to people blaming the low-rank “noob” for their own mistakes.
What I would like to see though, is my own MMR.
“PvP Rank” doesn’t really mean much, even people I know that just do their dailies are already rank 80. What matters is the MMR, but it probably is so broken that they are never going to make it visible.