IMDB should Rank Actors, Directors, Cast the way they rank movies..

Good idea!

That may lead to some conflict. The performance you mentioned of a movie may be either box office wise or popularity or based on critical reception. IMDB just shows what users voted for. It can't just shout out and say he/she is the best. It's based on voters views

I don't like the idea. In this climate, the door would open for trolling, and whatever forms of vitriol already plague all types of social media. Most of us could be fair and objective, but there's no controlling what may arrive from pranksters or grudge holders.