RE: "First, grading comes down to valuing a coin. It is valuation in the simplest sense."
This is a totally false viewpoint, and I've very disappointed to see it embraced by someone with so much potential.
The only valuation determination of a coin is between buyer and seller, and that is widely variable. This is easily confirmed by looking at coins of identical "grade" in auction results.
Second, the moment someone adds subjective criteria to the "grade" of a coin, the grade begins to float and is no longer a reliable indicator of the state of preservation of a coin.
TPG and other "grading" schemes are unreliable if opinion and potentially objective measurements are mixed.
Third, the entire base of TPG authentication and grading is independence from the money-forces of numismatics. If a TPG ever becomes a "valuator" of coins rather then an objective "evaluator," the whole pile of assumptions and grades falls apart. Coin collecting becomes just a self-serving pile of needy, greedy people conniving to rip the entrails from collector's wallets.