Ari,
the backset preloads the limbs at brace, which will give it a little more oomph for a given length, but I can't see it ever being as efficient in energy storage as a good D/R ratio. Like with anything, there are pros and cons depending on the goal in mind. I would imagine Steve's latest version shoots sweet because of a few tweaks and things they may not have known about back in the day that Steve is able to apply along with the backset, and/or improvements in glass and consistency in materials and glues now, who knows.