Since the line has gone to lows, it has been basically the same cushioning system for the 20 -22 with some tweaks. So, in an effort to do something different, they do the removable insert which basically eliminates people who either wear orthotics or don't like the feel of a removable insole.
Miss the days the line was mids or highs (they were of course heavier) and the line was more daring to try a different cushioning setup model to model and there was more latitude to do so because they were not limited low top silhouette. And you can only go so far in a low top with a line that is known for max cushioning and impact protection.