The movie you are suggesting be made seems like a tough sell (maybe the first "Bad Lieutenant"?). Cops tend to behave like D student bully types, sure, but have you ever watched the show "Cops"? That show is representative of cops' social milieu during their daily grind, biased toward entertainment value (drug users in it tend to also beat/cheat/steal/murder). Compared to the popularly exposed criminal representative cops are "glorious," which is to say, given a cop's power, the general popularly exposed criminal representative would be so much worse than a typical cop that there's no way not to sell cops as heroes to general audiences (i.e. there's no way for such a trend as you wish for in movies to happen). I think you and most people understand this, I just mean to say that in my perception cops aren't as glorified in our culture as many seem to think they are. They're only "good" in a relative sense that makes them potentially engaging characters in stories, not glorious.