As do I. For me, strength and durability is Gene's great edge over Corbett, who was knocked out in two title fights by a single punch. No individual blow is dropping Tunney for the count. Gene was much stronger than his 6'2" height and final competitive weight of 192 would suggest. No question about Jeff's foot speed. We can see him sliding forward, then abruptly get in Ruhlin's face from a seemingly safe distance. However, his hand speed wasn't remotely at the same level as Greb's or Carpentier's and it wouldn't have been able to match the sudden burst Dempsey produced the Long Count knockdown with. We differ here. I believe Gene could take those shots when Jeff did connect, but more often than not, Tunney's movement and defensive skills would enable him to evade that punishment altogether. Gene was extremely active with his jab, and Jeff would find it glued to his face continually. He'd need X-ray vision to see through Tunney's left fist, unless he kept his right close by to parry it aggressively. Over 15 rounds, he'd be too harried by Tunney's work rate to break through and produce the stoppage he'd need to win. Tunney would scout Jeff very carefully before ever stepping in the ring with him, and have him thoroughly evaluated by the time they squared off. He had the size, speed and skill to exploit any flaw he detected.
Is Tunney worthy to carry Jeffries spit bucket? Yes, but there is no doubt that Jeffries was the greater fighter. Could Tunney beat Jeffries over 15 rounds? I tend to think so. Jeffries would have to produce his absolute masterclass to finish Tunney in this period. Not ruling it out of course.