As far as actual on-mat action, this is the main change:
“Feet are regularly supporting the wrestler’s weight during the match while on the mat,” said Elliot Hopkins, director of sports and student services and liaison to the Wrestling Rules Committee. “We allow a wrestler’s feet to be considered supporting points while in a near-fall situation. By adding it to the list of usual supporting points on the mat, it will create more clarity and consistency for the wrestlers, coaches and officials – without creating additional injury risk.”
I always thought it was kinda laughable that the NFHS rules didn't count "feet" as "usual supporting points" in near-fall. Good change.