The reason the ratings on this manga are so high is due to the good character development given to those in the story, not because of the MC’s OPness. In fact, for a majority of the story, the OPness is put to the side in favor of progressing the relationship between our MC and wolf girl and building upon the plot and the world. On top of that, our MC is very mature, this isn’t a harem manga, and there’s a lot of cute fluff. Now, this isn’t to say that there isn’t any ridiculous OPness, but if another Shōnen series in One Punch Man can get an OP MC right, then so can others (not that I’m comparing this to OPM, of course. That web comic/manga is a goddamn masterpiece)