Adam has a great post about how managers can take what many perceive as a weakness and turn it into a strength.
His point is that if you consider a weakess is likely that the user is overdoing something, "which means that the person actually possesses a strength that they are just overdoing. Take away the overdoing and presto, what's left is a strength."
It only goes so far certainly - we are talking about personality traits (what quality is a developer who writes buggy code overdoing?).
I'm not so sure what the long term effects of promoting a weakness might be, but it is an interesting idea.
Do you have a weakness that you can "flip" into a strength?
Proudly Serving My Corporate Masters: Leverage Your Weakness