A copy, paste, and polish from a related thread made about a year ago:
I wouldn't like it. Why?
• Lack of diversity. It's not that I like running with bad players, but one of the reasons I like random stuff is the wide variety of different types of people you get. Running with the same (type of) people every time, all the time, would get boring fast.
• Reeks too much of apartheid/segregation. This sounds too much like forcing bad players to "sit in the back of the bus", keeping them from associating with anyone else at all. God help the Bads and Mediocres if one could find their rank just by examining them. They'd all be shunned by the FF community, big time.
• Doesn't improve anybody. Bad players won't get any better if they run with other bad players. It'd be like the blind leading the blind. They need to run with players better than themselves so they can see/be taught how to improve. Presumably this was why the mentor system was put in place (although me, I think it's redundant though).