I agree with this.
Simply b/c a dog has never had to display heart to win doesn't mean the heart isn't there.
DOY is about performance and there is a lot to consider. More than all the different abilities, keeps, handling and gameness. There's a ton to consider. So, b/c there are so many ways to win and so many ways to lose, DOY accolades should not consider one component over the other, but rather sum of all components.
Gene Stallings went to Bear Bryant about a recruit for football one time. He was super excited. Kept pointing out how, no matter how many times this young man got knocked down, he would always get back up and keep coming back for more. Showed Coach Bryant countless examples of how this young man would always come back for more, no matter what happened to him. He finally asked Coach Bryant, "So what do you think". Coach Bryant didn't hesitate. He simply said, "I want the guy that keeps knocking him down"
Winning is about winning. Doesn't matter how, especially in a sport where there are so many ways to lose. One freak "Fear Bite" from a cur that is losing drastically from the bottom can end a fight or even the life of a truly great animal.
So no, I don't think gameness should carry more weight in selecting a DOY candidate than other components. I think it is definitely a consideration, but no more than a lot of other components.