Again, the question I have is WHICH 51%? Most ARFs have non-scale lines and no detail or scale finish and may take a lot of work to address these issues to make a competitive scale model. Traditional Kits (Short from plans or full) may have good outlines, but again, all detail and finish must be done by the builder, in addition to the construction. Composite kits, in some ways are the exact opposite of of an ARF in that with many, virtually all the scale and detail is done out of the box, except for finish, but none of the construction is done. The amount of work needed to complete one may be as much, or even more than framing up a kit. But being a scale competition where the static score is judges the outline and detail against the provided documentation, is it fair to equate the time spent on general construction to time spent on researching, designing and implementing modifications to kits or even ARFs to be true to scale and to add all the detail, panel lines, hatches, rivets, surface textures and so forth?
As for someone who builds a model from scratch using composites (creates their own plugs, molds and pulls their own parts), to me, that's a different story. It's not the material the model is made from, but who has done what work. In this case, all the work has been done by the builder and I don't think any points should be deducted.

Now all of this has to be put into the context of which category we are speaking of. I think many, as even I did when I started reading this thread, are assuming we are talking about expert. I do think the introduction of new classes to encourage more participation is important to the continuation and growth of interest in scale.