@MaTu94 So you mean a series like One Punch Man, where the MC is quite literally a blank slate and apathetic towards the events around him, and the story/events gets carried by the side characters that represent a cliche, and the main characters play an ex-machina, right? Don't pin this down as the author's poor writing, it's not. It's not a terrible series, this just didn't live up to your expectations. Just say that, it would still be understandable.
The MC of this series was literally absent from civilization and the world itself for 500 years. He comes back and just becomes the guard of a barrenness. Please explain to me, what political standing or influence should he have over the world of the manga itself. What reason would he have to do anything beyond the events that have coincidentally fallen upon him, thus far? He's beaten the hero, does that mean he should be the hero instead? Your idea of criticism is that you dislike the direction the author takes his story and describe them as flaws. A flaw would be an inconsistency in the writing, like a plot hole, an unmotivated plot twist, an unreasonable power up, etc. If your main argument is that you dislike the MC being boring while the series itself is telling you that, then you're mistaken. If your argument is beyond that, then please. Take your next comment to explain that because you clearly failed to do so in your previous one.
P.S Nobody is trying to be smart, nobody claimed to be, the fact you exclaimed something as such shows your own insecurity. I just wanted to point out the fact people have forgotten that the main character is supposed to be boring.