What you have to do is come up with a large list of professional and technical competencies. Then both the employee and the manager need to select 3-4 that need to be addressed, and come to agreement on those, and then upon each assessment then there is both a management assessment and a self assessment. As each of the weaker competencies become stronger and more well rounded, then you can focus on other competencies.
Be careful on how you do this, because if people really get wind that you are all of a sudden looking at everyone's competencies that usually means that you are looking at eliminating people.
You have to present it in a manner that demonstrates that this is a plan whereby the employee can achieve a desired goal.
Get rid of the meets exeeds outstanding does not meet, unsatisfactory chart - either you are making it or you aren't, either way there has to be a plan. A goal. Present it always in the manner of here's how you can better yourself - I think most people want to better themselves.