I'm confused by this thread. Most of the holes at OTB were demanding, but offered a wide variety of lines. You had plenty of holes where 3 or 4 people on the card threw different lines from each other. There were many rollers, sure, but many other shots as well.
The huge advantage Swenson had over many other ball golf set ups is the prevalence of so many mature oaks. That meant that you had wider alleys with low ceilings. Off line shots were punished, but usually didn't result in the same kind of punishment that, say, firs would. You couldn't make the same kind of interesting course with other kinds of trees. Oaks rarely result in NAGS, not so for other bunker trees.
Even if we just compare a roller or air shot on, say, Emporia or Goat Hill, to Swenson, the general setup of Swenson usually meant that the shot was crossing a variety of obstacles and terrains. You didn't have a shot running down a wide open fairway being launched from what seemed to be the ball golf tee. Most of the holes were composed of multiple pieces of ball golf holes, or completely separated from them.
Then you have what was far more natural OB. Even though there isn't much of a practical difference between the Swenson ponds that had an OB line, or "ponds" created from OB lines, it's still more visceral to see a shot trying to clear water vs. trying to clear string. While there were some artificial OB lines, they mostly didn't come into play. Avoiding OB lines was not a primary source of challenge on the course, which is quite rare for DG on ball golf properties.
Take hole 10 and imagine pushing the pin back and left so the green and the bunker were more in play. That would have made a much harder hole, but probably a more arbitrary one. As it was, the hole was the easiest on the course, but good shots were rewarded, and bad shots took birdie mostly out of play. It was in harmony with the rest of the course, and forcing the green or bunker to be a major obstacle wouldn't have been.