A character be physically strong, but not look it. Because in reality, physical conditioning and strength have visible indicators. So yeah, I totally agree with you there. Sanosuke and Kenshin himself kind of piss me off in this way, from Rurouni Kenshin. So do Cloud and Sephiroth from FF7. You skinny bastards don't actually have muscles and need to eat so I call BS on this whole deal! Pretty sure this is a kind of a culturally based thing so that the skinny majority of the japanese audience can relate that much more to the main character. Pretty sure Godot and I mentioned Ryu's height and weight... and how I would actually be way above him in both height and weight. Puny mortal Ryu. pfft.
And yeah, the anime where the main male protagonist is useless except that he somehow always stands up in moral situations and somehow has some kind of special power only when he's under extreme pressure to use it is annoying AF. AKA, gohan in the cell saga. AKA most main characters in harem anime. They try to give him a legitimate redeeming quality via bloodline trait that is OP and go half-assed and try to make him seem deserving of it because of his innocent, morally righteous character. yeah right. pls.