We did something like this in FFXI, would tell people on our servers who to watch out for, etc...

The problem with this is that a lot of the issues seem to come from people being rude in Duty Finder. You don't know what server they are from using Duty Finder unless they tell you. So if I said. "Hey FLUFFY SWEATER was rude to me in Duty Finder, they did X, Y and Z to me and don't play with them."

Now what if there are 5-6 different people named Fluffy Sweater? Are people going to be rude to all of them and go "Oh well I heard about you from the OF and you're rude" and then innocent people who did nothing wrong get blamed for one person actions? At this point with the way SE has things set up, and the Duty Finder it wouldn't work. So this would cause more harm then good.

I agree that it is good to try to help the community as a whole against rude players, but this tactic won't work at this time with the way the game is with Duty Finder (which I avoid at all costs).