You didn't even get the point.
I said that you can derive more information from a dominating performance over several rounds than you can from a quick KO. That has nothing to do with saying that it's not great to finish someone quickly.
Anyone can get KO'ed in MMA, but anyone can't dominate another fighter. You need to be better than the other to dominate and that, in addition to that you get more time to assess their skills and to lower the influence of freak occurrences, makes for much more information to base opinions on when you're predicting how another fight between the two combatants would follow.
I'm very proud of my results in martial arts competitions so I'm not ignorant about what it's like to fight (I never did MMA though) and, while I certainly did not want to be knocked out or submitted, I know that a rematch I would have the least confidence going into is if the opponent had just manhandled me in every area without me being able to stop him. If I would get rocked or submitted just due to me making a stupid mistake I'd be more confident that I could change the outcome the next time, just because there are more unknown factors to play with. In any case, I don't like to lose no matter how it happens. If I could decide how to win I'd of course take a quick finish since that lowers the risk of me being banged up and it's less work but, as said, that wasn't the point.
Fair enough, at least you've competed so you know what its like. I still disagree.
In terms of confidence, I was always more nervous about facing someone who'd finished me (I did judo nationally and wrestled in college) by an ippon or pin than someone who'd just run up the score on me - and I think it'd be worse if I'd boxed or did MMA. Especially being pinned in wrestling, it was humilating. Knowing that my opponent could, if I made a mistake, finish it that quickly was always daunting. Someone who'd dominanted me I could work on for the next fight, because it was usually a number of small things, or tactics, and knowing they didn't have finishing power always gave me hope.
Which brings me to your second point. I think we learn one very important thing from a quick finish and a domination that you're overlooking - the person who finished quickly has finishing power, the one who dominated for five rounds but couldn't finish doesn't, but has better general skills/abilities. The abilities are actually almost orthogonal - its actually fairly common for someone with great finishing abilities to be lacking in general skills, and vice versa.
And I still disagree about freak occurrences - as much as I hate to admit it, when I was pinned in wrestling, or thrown for an ippon in judo, it wasn't my opponent getting a freak occurrence stroke of luck, it was them doing the right thing at the right time with the right abilities. I'll admit I sometimes muttered something to the effect that they just "got lucky" afterwards, but that was just trying to save face, the fact was, their finishes, like JDS's, involved a lot of skill and ability. And when I won by a pin or ippon throw, I knew it wasn't luck, because I knew what I did, both in training and on the mats, to set up that pin or ippon. As you probably know very well from your own experience, what looks like luck to someone watching is almost always something earned by countless hours drilling, and clever setup once in competition.
What it takes to grind out a dominating decision and what it takes for a quick finish are different, but both are skill based, and both tell us a lot about the fighters. JDS has very good finishing ability, better than Cain's. Cain lacks JDS's finishing ability, but has better general skills. The first time JDS's skills dominated, the second time Cain's. If they fought again, I wouldn't bet my house on either, because the skills are at cross purposes.
