Implement a personal rating/performance system

[RushRiviera]

This right here. It may only be personal, but people WILL demand screenshots. It's not possible for something like this to even exist without causing it to be used to exclude people. Never underestimate the lengths players will go to.

Even if we disregard all the things in my previous post above. This can be accounted for simply by making sure the majority of players fall into a B rating. Meaning that only the lowest 5 or 10% would be rated C, and to get an A you need to reach the top 40% to 30%. This means 50% to 65% of players will fall into a B rating. Such a wide range within B means that knowing someone is a B rating doesn't give you much specific info. Nobody is going to keep kicking party members until they eventually find someone who is in the top 30%, and if they do it's very easy to find and flag that kind of behavior.

And if you're playing with someone who falls into the bottom 5% I'm pretty sure that will be painfully obvious without even needing a rating system.

Edit: Actually I've added this into the concerns section of the first post.