I do agree with you, Gheorghe. Hard textures predominate. Sonny's touch is very percussive and hardly resonates at all. (I hear something similar in Walter Davis of the same era.)
Jackie, too, of course. Compare him with the much softer sound of Hank on Dial S for Sonny. That album has Louis Hayes, who is considerably less hard and aggressive than Philly on Cool Struttin'.
The only player on the album whose "hard" credentials could be questioned is Farmer, who was sufficiently versatile to be a member of the Gerry Mulligan quartet not long after.