Your thinking of two different types of intellect, you think fighting is all about instinct and its not. Let me, let you know something.The reason why you are misguided in the first place is because you assume im talking about book smarts, which im not. Truly if you could see beyond the word "intelligence" you would know that there are many different types.
Even this "instinct" word you keep throwing around is simply not applied to just H2H combat.
"Man I couldn't figure out question 42 on my test but my instincts keep telling me to go with C."
"Was it right?"
"Sure was!"
You see, although he didn't know the answer to the question, something keep telling him the answer was C. Maybe the answer was posted on the board a few weeks earlier and although he didn't read it his mind sublimely picked it up. Or he may of been reading it one tired night and again didn't register it but his mind, sublimely, picked it up. When it came time for test day, although he couldn't remember where he saw it or why it looked so familiar, he somehow knew the right answer was C. He didn't know why or how, but he knew that was the right answer. (although if he would of actually studied and payed attention he could of saved himself much hassle during the test and intelligently picked the right answer.)
Lets apply this logic to fighting.
Most pro fighters are already in amazing condition and although they still work out religiously, how can one get better at fighting?
You say the professional fighters fight with nothing but instinct, remember you said intelligence doesn't matter. But if that's the case, why do they study tapes so hard before a big fight?
They watch, and watch and watch and watch and look for small holes in their opponents defense in which they can exploit. They practice and practice on their own weakness because if they are an "intelligent" fighter they are already going to know their opponent is putting in the same video review looking for any weakness in their game.
After many weeks and long hours of practice and review fight night arrives. He's gathered everything he knows on the fighter and at the same time worked on his own weakness.
In all the tapes he's watched he knows, that his foe is absolutely horrible at defending the overhand right after committing to an attack. He also knows that his opponent is amazingly strong and with but a few clean blows can put him down. He already knows to intelligently watch his punches, for one false move may be his last.
As the fight starts and goes on his body starts to, hmm, not really forget about the overhand right , but its no where near the forefront of his thoughts.
This is where, battlehammer your instincts take over, but not in the manner you speak of. You see because he studied the fight so much, he now doesn't have to think about how strong his opponent is, his body knows it, he doesn't have to think about watching his punches, his body automatically does it for him.
His body is on auto-pilot and everything is a controlled blur (any body who has fought organized before knows what the hell im talking about).
Suddenly his foe commits to an attack and NOW his "instincts" take over. His body automatically throws an overhand right, he didn't think about, his body just did it.
Clean hit, his foe goes down, fights over.
Do you see where Im coming from battlehammer?
Yes his instincts may have taken over but, it was his intelligence that gave him the edge. He wouldn't of instinctively knew to throw that punch if he didn't put in the long days of work. He studied his opponent and it paid off.
And although the fight ended with an instinctive Overhand right, the punch actually originated from a small gym, or even a house, where the fighter sat by himself or with his trainer, and found out his opponent was weak against that punch.
Now im not saying intelligence wins every fight, hell im not even saying it wins a majority, I mean crazy s*** does happen.
But what I know for a fact is that intelligence DOES matter.