Logan is something extraordinary emerged from the Marvel brand. The theme isn't entirely superhero all the way, it has subtle hints of realism along with a blend of Western Classics. It isn't about the type of heroism beyond the magnitude of the subject.
This Logan is quite similar to Alan Ladd's 1953 classic Shane, where the protagonist indulges into the trajectory of someone else's fight, which gradually turns out to be ineluctably personal.
Logan is certainly the rarest gem in the crown of superhero movie genre. It changes the way we are accustomed to look at superhero movies and also it sets a benchmark, which I doubt can be touched by any other.