I had a Maat's Cap 'back in the day' before they trivialized leveling (mtultiple times). Maat wasn't even remotely challenging. There were some gimmicks that were easy to get around by various methods for several jobs, but that was basically it. Also, there were tons of people at 75 that were still terrible at their jobs regardless of having cleared Maat, so it didn't really keep the baddies at bay, or whatever it is you're hoping will happen with this idea.

As some other people have mentioned, if you want super pro groups, make one. Otherwise, don't expect every DF or PF player you run into to be super pro. I'm pleasantly surprised when I get good groups in DF, and when I don't...well, that's just part of the experience with MMOs. Everyone comes from different gaming backgrounds, and you aren't always going to be matched up with people with skill equal to yours.