The average shotgunner simply lacks the means of taking 3d patterns. 2D patterns are certainly not totally irrelevant. For at least 90% of game or targets shot shot stringing simply results in a slight elongation of the pattern, direction determined by flight direction of the target. 2D patterns with holes will still have holes or at least very thin areas in them while those without holes will not pick up big holes. A "Well Distributed" 2D pattern will result in a good 3D pattern.
For "All" shooting forget the existence of the "Square Load" & for the vast majority forget you ever heard of "Shot Stringing".

Miller/TN
I Didn't Say Everything I Said, Yogi Berra