David,
I agree with your issue. Some people get overlooked and kind of lost over the years. That being said, it does take tracking or documenting different issues. Once a list of issues is made, presented as a training issue rather than discipline, it is usually received much better.
Complacence also comes into play. I feel for you, I've had similar issues with certain people. The fact of holding grudges rather than taking it as constructive isn't right.