Keep in mind that MS coins are judged mostly on dings and scratches … a MS60 has a lot more than a MS65. However, circulated coins are judged mostly on wear … a XF has more than an AU. But an AU55 or AU58 coin can be a lot more attractive than a low-grade MS coin. If not for the slight wear, it might have graded MS66 or MS67. There is a mystique about uncirculated coins that they must be more attractive than any circulated coin. After all, they are Mint State. And this idea is usually reflected in their value. I think there should fewer MS grades. 11 is too many, and plus and sticker grades make things worse. And perhaps a suffix letter for circulated grades to indicate the number of dings and scratches … 40a and 40b for example. Many times, I’ve looked at XF or AU coins and thought, “Yeah, very little wear.” But some look like they’ve barely been handled. Others look like a herd of cattle trampled them. Mike
Not only that but does: "buy the highest grade coin that you can afford" make sense anymore? How long has that mantra been around, a hundred years? Back when someone thought that up grades went from Extra Fine to Uncirculated. There was a big difference in how each looked. It may have made sense to pass on a Extra Fine at $1 for an Unc at $2. Today there is little difference between grades and big differences between prices.
...and the grading standards keep slipping and sliding, so that 65 you stretched for ten years ago might be an albatross - unless you pay to have it crossed or reconsidered to be a 67 by today's standards, or pile beans onto it. The winning move is to "buy the coin, not the slab", possibly raw, if you're confident in your grading ability. But then the 65 you bought, which would be a 67 from today's graders, will suddenly be a 62 to the person you're trying to sell it to.
It was simpler before but at this point I would not eliminate any of the grades. It would likely cause more issues and make it confusing when you are comparing an "older" holdered MS 63 to a "new" MS 60a. The one "innovation" that has popped up in the last few years is the NGCX 10 point grading scale. That does not appear to have caught on besides VaultBox and other mystery game slabs.