I would agree with the posters that the routing of SFGC is not as complex as Merion's. After all, SFGC is a rectangular site ... Merion has little corners, streams, a quarry, a road crossing, etc.
I would disagree with the premise that having a lot of east/west holes in a routing (or a lot of north/south holes) is a weakness. Sometimes that's what the property gives you. Let's take the front nine at SFGC as an example:
Obviously you are not going to play north and south over the valley on #7 and #8, so those holes are routed first. With those in place, it seems like a good decision to play #6 along the rim of the valley, doesn't it? Three holes in place.
Now, how far do you think it is from the first fairway to the fifth fairway, if you wanted to run the rest of the holes north and south? It's somewhere in the neighborhood of 300-350 yards. Plus, you want to play #7 going east, which means you need to play #6 going west, which means you can't have a bunch of north-south holes starting from the clubhouse without having a hole to get back from the west end ... and if you built that hole (either #5 or a backwards version of #1), then the north-south holes would only be 200-250 yards long.
Generally speaking, once you start playing a couple of holes in one direction on a rectangular site, it's difficult to not keep going that way. The fact that the valleys on #2 and #7/8 at SFGC both run east and west makes the rest of those holes play east and west. I suppose the back nine could have had more north & south holes after #11, but I believe that the original green site for #12 and the view on #18 prompted those holes to be routed east and west, and everything else followed from there.
It's a very good routing.