+1 this wholeheartedly.
Like you said, I'm not sure if I'm missing some kind of feature but it seems that there's no way to quickly adjust multiple specific layers at once without making an adjustment layer, duplicating it for every layer, clipping mask and then merging with each one which takes a rather long time.
It seems like the script you linked also allows for applying the adjustment layer only for selected layers, so it would solve this problem as well!