I am quite amazed no one ever suggested this before (or they choose a very in appropriate topic name and I missed it).
Since Wow-heroes is used a lot in conjunction with finding a proper PuG it would be nice to see someone's gaming skills instead of just gear.
Measuring skill is quite a difficult task and measuring social skills is well.. undoable.
So wouldn't it be nice that after you ran your PuG with people you verified on Wow-heroes you can rate how they performed during your run and add a comment with your rating.
Personally I was thinking about a simple thumbs up thumbs down system and I'm sure you can come up with a good flooding system for it as well