No one argues about VF Indian Cents. For 90% of the grading, regardless of Brown & Dunn, ANA, PCGS, Red Book, etc., the criteria lead to the same result. So, you can go by "three letter of LIBERTY" or compare a picture, but the grade is the same. It is where the differences are that the discussions begin. It is not so much that "experts" define grades as that experts report grades. That reporting is a reflection of what the mass of "collectors" and "dealers" seem to believe, so it comes down, as you say, GD, to either getting everyone into lockstep, or else accepting the existence of pluralism. Again, however, I stress that for whatever minor differences, grading is the same for 90% of American coins.
I think that would be better if you said VG...if you mean VF there should be more than just 3 letters..... Speedy