How about this: take Tyson in his prime and clone him and call him Tyson2. Give Tyson2 D1 Wrestling, Mundial level BJJ, Muy Thai... who wins? All else being equal the MMA fighter wins simply because they have more tools. Stop with the silly arguments and inane comparisons.
I also want to address this issue of MMA fighters having weak chins. Friends, we all have weak chins. If you've ever been hit on the button something special happens to you. It's not like getting knocked out by the sheer force of a punch to the cheek bone. It's much different. That little spot on the chin is a very special place. And boxers know that and have generations of training to defend that particular spot that it's just second nature.
Boxers compared to an MMA fighter have a very limited target area and they know about the chin. That's why boxers hold the hands the way they do, and tuck in their chin the way they do. And why it's so much harder to hit the button if you are a boxer. You hold your hands like that in an MMA match you will get taken down at will and have you legs kicked and kneed to death.
Unless you are a Neanderthal, it doesn't matter if you are a boxer or an MMA fighter or a bouncer, take it just right on the chin and it's lights out.