GM, I hear ya. In the class I take we do a lot of impact conditioning, kicking and punching one another. I drop at least once a week from a leg kick. I think taking all that impact has helped me respond more honestly and calmly when I spar. There are still limitations though. For example, the other day when I was sparing I got tapped out by a guy who did a double leg on me and then got a mount. While it was happening, I did like 5 downward elbows on his neck and then grabbed his trachea, not hard at all of course, because those sorts of things can't be.
Who's right? I'm happy with how I did because I think if it was real, I would have won. I don't know the guy, but I'm sure he thinks he won because he tapped me out. Impact can teach a lot but its the little things that kill - biting, grabbing necks and eyes, breaking fingers - but it is hard to show that kind of stuff in a sparing match in a way that gets the other person to understand what happened, unless they understand intellectually outside of the match already.
Even with a lot of impact, I'm not sure how to get the chaos of a real fight in sparing, or even organized fighting, because everyone knows you aren't really going to rip out an eye or break a finger, so people take chances with really, really dangerous moves, like tying up both hands with a wrestling take down. I think a lot of people on here have been in a lot of real fights, but I haven't, because I'm too good at talking my way out of them and I'm not a cop that's forced to fight with people.
I can train myself pretty well because I can mock go for an eye or a neck or mock bite, but I don't know that I would really do those things because I've never done those things, and really fighting isn't a natural thing for me. On top of that, doing those moves in sparing without hurting the person fails to educate them, so the community doesn't improve either.