DiCaprio is actually 5’11” and depending on the role between 170 and 190 lbs. Above what the current national norm should be, well above the average in the 1800’s and the Viking era.
I know we romanticize the Vikings as the 6’4” blue eyed blonde haired muscular ubermensch but in reality they were 5’6” blue eyed blonde haired muscular maniacs.
OK, a skinny 170 lb. pretty boy. I just can't see the toughtest NYC gang banger in the time before widespread posession of handguns as an "average" sized person. I picture a intimidating tough guy and Leo just didn't fit the bill. As I noted, I thought he did a good job acting but it was too much a stretch for me.