Interesting, that of these three swarmers, Frazier, Marciano, and Dempsey, Frazier looks like he's the hardest to hit (give you up and down along with side to side head movement, makes himself even smaller by getting low), yet, of the three he's most likely to get hit the most in a fight. It sounds contridicting but of the three he puts the most pressure on, therefore he is taking more risks.
Put it this way, I'll bet Frazier's opponents miss him more often than the other two. Of coarse Marciano and dempsey will give foreman a better fight than Frazier, but Frazier's a harder fight for Ali than the other two (not saying they'd be easy for him). Interesting, that Marciano and frazier are labled as slow starters, while Dempsey and Tyson were fast starters. Although Tyson's murderous pace is only going to be about 3-4 rounds, then odds are he'll get discouraged and/or fade. Excellant point about Marciano's bound to get hit comming in against Charles, Walcott, Moore, and the old Louis, they are not only pin point punchers, but they can JAB. The jab is the biggest obstacle for a swarmer (although a right uppercut's another problem). Tunney's about the first big time jabber that I've seen Dempsey fight on film. The sport's evolving in the 1920's