Lack of variety in Oscar nominations

At the 89th Academy Awards the Makeup and Hairstyling body decided to do something unexpected and awarded the critically panned Suicide Squad.

A bold move that has always got me wondering why don't more categories do this. A movie is a sum of its part and the Oscars is a way of honoring those parts but yet it seems each category follows a trend and awards/nominates the same films. A movie can be bad to average yet still have amazing editing, score, sfx, production design, etc. Yet you don't still see varieties in those categories.

I understand that a "good movie" is a movie that does all those things right so it's expected for there to be some overlap but at the same time I'll love it if some categories just does its own thing from time to time