Yes he was a very intelligent fighter with better skill than most. Most of his fights will illustrate this.
Just watch his fights. He was dominating truly world class fighters by the time he had his tenth fight or so. Opponents were hard-pressed to win a round against him, let alone a fight. He was brilliant.
Sweet Pea in ways reminded me of Nicolino Locche with great defense and movement. Although Sweet pea's record seems like small potatoes when you put it next to the Untouchable's record, Pernell was one of the greatest fighters of his era. I would have liked to see ODLH and Pernell run it back but that time has passed.
I know he had great defense. I'm asking was it off athleticism or did he have a great ring iq on top of it? Did he make any mid fight adjustments or change his style based off his opponent?
Yes. His whole career Except maybe when he pulled Roger Mayweather's trunks down enraging Mayweather who then dropped Whitaker.
I always felt Pernell was very well prepped before his fights, yes he would do tweaks as he went along, but I feel he had his fight plan pretty well in place before each fight. So I can't suggest any specific fights where he switched it up suddenly, he wasn't ever really in any fights where this was needed IMO. He was simply too precise and measured. I think his IQ was mainly in his ability to have a solid game plan and build a style that for a period was able to deal with any style he faced and master it. Put another way his style was specifically made to avoid letting his opponents spring any surprises. You could suggest that after the Ramirez fiasco he could have adjusted his style to be a bit more aggressive and avoid later screwings vs DLH and Chavez by forcing the action in the later rounds more to seal his victory, knowing he was being judged by blind or corrupt officials.
Greg Haugen rated him as the best fighter he ever fought "hands down." That's high praise from a guy who did not usually praise his foes.