He does not have mediocre wingspan though. 6' 10.5" wingspan and 8'7" standing reach. Pair those with his insane jumping ability and body - you have someone who plays much bigger.I do think an inch makes a difference. 6'7" with mediocre wingspan is small for a PF, very small nearly unplayable for a center. 6'6" with mediocre wingspan is probably unplayable at the 5, and is starting to be an issue at the 4. It's partially what the height also tells us, we can look at him and see his reach and wingspan ratios to his body, if he's 6'5" or 6'6" there is an effect on reach and wingspan, and those are very important for the ability to play a "big" position in the NBA.
At this point the dude is a concensus top of the draft pick. Seems folish to focus on what he can't do