If you think about it, they pretty much do have two grades. The Sheldon scale with the numerical fractional after. Do we really need any more? Nope!
This is another serious deficiency with TPG. Basically most coins are in holders given the highest possible grade. Think about it, thousands of collectors scour the market evry day looking for a coin they can possibly "crack out" to get a higher grade. Who searches the market for "crack outs" to send in for lower grades? No one. This is why, to me, any TPG grade is the highest it possibly could be, with a strong likelihood it could very well be a lower grade in a higher grade slab. If all TPG used cameras to record each coin, and each coin could only ever be slabbed once, I would have more respect for the process. Chris
Not enough grades at this time IMO. Sheldon X 10 for starters, a 700 point grading system. And then an advanced star, plus or other system or negatives on the holder too, minuses, etc..