Wow...EXCELLENT debate question.
No one here would deny the Gable/Owings match. But, let's consider that that loss lit a fire so deep inside the G-man that he tore through the Russians, then the Olympics, then the NCAA. One record I saved from somewhere states that Gable beat Owings 7-1 in an Olympics trials match in Minnesota in 1972, so he got his revenge. It's a tough fantasy choice.
I still ache watching the video of the McIlravy loss to Marianetti. That denied him (and us) of a 4x champ to match Steve Smith and Cael Sanderson. The honest truth is that Marianetti was good, and it is less painful to lose a match to a truly gifted athlete.
So, I guess that I still wince more at Dan Dennis' loss to Jason Ness in the 2010 final. He had #1 Ness beat with a couple seconds on the clock, but backed up while Ness made a desperation lunge, got taken down and gave up two backs. Ugh! If only he'd stood his ground and put up even conservative defense, he had it in the bag! What really makes me ill--and I'm an ordained minister for crying out loud--is that Ness gave thanks to Jesus for the win. Oh, the nausea I felt.