The DCRA briefly toyed with the concept of allowing 4X scope on target rifles but I don't think there was enough response to keep the rule in effect. Personally, I was all for it. I can buy and mount a lot of four power scopes for the price of a good set of irons with diopter.
The advantages of optical sights go beyond just being able to see the target. The large field of view reduces the chance of a crossfire. Positioning of the eye remains the same at all ranges.
I felt that a Leupold or Weaver hunter class scope, knocked back to four power and with a two minute dot, would have made the perfect TR scope but the door was closed. To me, the option to use a low-powered scope just makes sense. Properly promoted, such a change might even attract new competitors. GD