What separates the pros from college players is overall speed. Everyone can run in the NFL.I happen to believe that football players are not so stupid that they would endanger their lives while playing. They would quickly develop techniques and skills, the rules would be modified a bit, and the overall number of injuries - particularly head injuries - would be reduced.
There are many sports where a normal-sized person can excel. Baseball, tennis, soccer, golf, bowling, hockey. As noted above, there are a few positions on the football field where a normal-sized person is not at such a ridiculous disadvantage that they can be competitive. But basically, that the highest levels, football and basketball are reserved for mutants.
No thanks.
While some positions require larger than average size, many positions on a football team do not.
2013 NFL draft - Five-year NFL combine averages - ESPN
That link shows the averages of all the players in the combine from which the NFL drafts its players.
The average height & weight for a QB is 6'2" and 223lbs.
The average height & weight for a WR is 6'0" and 202lbs.
The average height & weight for a RB is 5'10" and 213lbs.
The average height & weight for a ILB is 6'1" and 241lbs.
The average height & weight for a OLB is 6'1" and 238lbs.
The average height & weight for a CB is 5'11" and 193lbs.
The average height & weight for a Safety is 6' and 208lbs.
None of those look like mutants. And these are the 5 year averages for the top level college football players coming into the NFL.
Those combine numbers are for kids coming out of college...so essentially irrelevant compared to veteran nfl players