I think there are currently two main issues with Pantheon.
1. People dropping because they are trying to get into premade teams thus game the system.
2. Lack of trust on players part that the system will make relatively balanced matches, partly dues to people gaming the system and also because it sometimes makes bad parings.
I don't think it is an easy problem to solve though. On one hand it would be nice to know more information about the players in the matchup without having to look it up on the Pantheon website. On the otherhand, some people might be more inclined to drop when they see that they are going against some tough competition.
For example, you are 3 players with ranks in the 10-11k range and you are pitted against two players in the top 50. Stay or leave?
What about you are in the top 50 and partnered with someone in the 20k range against 3 players one of which is in the top 100 and the other two have ranks between 6k and 15k. What do you do?
I've seen similar cases to these two examples so I know that the Pantheon is doing these matchups. I can also tell you that people will react differently to these situations. Some might stay, some might drop and some might do a bit of both.
If they where going to do a more informative interface I'd suggest an interface similar to the one used in custom games where it show who is playing on each side and what their rankings are. The match making system automatically adds players to the match if spots are available based on rank balance. Players are free to chat with each other while waiting for the match making to complete. If they don't like the match they can drop and the match making system will find a replacement. When the game fills up and everyone agrees to play then they all click the ready button and the game starts. This sort of match making will take longer but should also give the players a greater sence of trust in the system. Part of the reason that I think this will work better is that players can chat with each other while waiting which makes the wait feel less long and builds a sence of community.