Bo Jackson is one of the greatest athletes of all time. He could have won gold medals in about 4 different track sports + NFL all star + MLB all star + Heisman winner.
Bo was a freakish physical specimen, but there's waaaaaay too much hype re. his multisport prowess.
* He was a great running back in college but there have been many who put up better #'s, including contemporary Herschel Walker who was even better then Bo. His NFL career was very abbreviated by both injuries and his attempt to play baseball. You can't be the best as a part-time player
* He was really fast for a big guy, but he was not an elite world-class sprinter and certainly not a threat to medal in the olympics. His best 100M was 10.44 in 1984 which is .45 seconds slower then the time Carl Lewis ran in the Olympics that year. That is a HUGE gap, and Bo's best time wouldn't put him near the top tier of his era.
* He was good enough to be a major league baseball player (which is saying something) but he was an unremarkable low average, high-strikeout, & low walk/OBP (career .309 OBP) slugger. He was highlight reel flashy, but not a great ballplayer and particularly suffers with some of the more sophisticated stats used to compare him to other players (eg. WAR)
Calling him a better athlete then Federer is in large part applying the eyeball test of raw strength and sprinting speed. By more subtle metrics of agility, stmina, and technique (and certainly by actual results) Federer blows him away. Wayne Gretzky suffered in that comparison as well. They're both normal sized guys with insane gifts but aren't build like bodybuilders