For athleticism, I remember being impressed with Chris Carr. He didn't play much, but he could sure jump and dunk.
I'm going to define athleticism as a combination of strength, speed, quickness, agility, coordination and leaping ability.
Kevin Johnson had all of these things, so did Amar'e Stoudemire. Most of the people mentioned fall short in one area or another. Dumas was a great athlete, but unfortunately it stopped at his neck.
Danny Ainge is the only high school All-American ever in football, baseball and basketball, played in the major leagues and won the Eastman and Wooden awards his serior year at BYU. Why isn't he mentioned?
Charles Barkley and Shaquille O'Neal were athletic freaks. Ronnie Lee was drafted by the North American Soccer League, NFL and NBA.
Basically, it's an impossible question to answer.