AC/20s do have the advantage of concentrating the damage to a single location, regardless of psychological impact. Getting a location destroyed affects a game a lot more than just losing armor all over.
Of course, Swaybacks tend to carry way more lasers than just four, so they have higher damage output overall, which probably ends up being more important.
Speaking of Hunchbacks, does any advanced Hunchback variant compete with the Quasimodo is it an upgrade over any and all?