Kind of disagree with you there, breh.
Both the hero and villain are important, but they don't have to be equal sides. Like RDJ completely outshined every villain he had in his movies, but Joker completely outshined Batman in TDK. Rambo outshined his villians, John Matrix did as well, etc.
To me, it depends on what kind of story you are trying to tell. I feel like a lot of cats are either limiting their perspective on what a good movie could be or completely biased to what they like in a movie. We all have different preferences, but the movie I choose to watch is what it's billed as. When I go see an Iron Man movie, I want to see IRON MAN, fukk a villain. TDK was basically a Joker movie, which was great but Batman was close to a non factor in it. When I go see a Rocky movie, I want to see a movie about ROCKY, not specifically about everyone else.
And keeping it real, I had absolutely no problem with Loki, Ronan, Winter Solder, Iron Monger or most of the marvel villains, but they mostly all pale in comparison to the Joker, but each and every one of Marvel's heroes outshine Baleman too. I think its more about what you are looking for in the movie.