The only real unbreakable rule I have about flawed characters is this - I need to know that the writers realize they are flawed.

Agreed, with the caveat that I need to know from what makes it on the screen—I'm not really interested in all the Confidential stuff, and the show should speak for itself. Who does this some of the time for me, but falls through on it at the weirdest moments (GitF, LotTL, FoB, etc.).