Does "lesser" as in "lesser man" refer only to moral strength and goodness or can it encompass physical and mental stamina?
NOAD gives the meanings thus:
lesser not so great or important as the other or the rest : he was convicted of a lesser assault charge | they nest mostly in Alaska and to a lesser extent in Siberia.
• lower in terms of rank or quality : the lesser aristocracy | you're looking down your nose at us lesser mortals.
• used in names of animals and plants that are smaller than similar kinds, e.g., lesser spotted woodpecker, lesser celandine.
But that doesn't tell the whole story. The term "lesser" may refer to someone who is not as great as another by any measure one chooses.
I can drink 12 beers in an hour, where a lesser man might manage only six.
Karen was no dummy, but her mother always considered her a lesser light than her sisters.
Sir Robert the Lesser was called that because he was nowhere near as corpulent as Sir Robert the Greater.