I think you nailed it with “my priorities would be ….” This brings to the fore how subjective grading must be. This does not, of course, mean that there is no objectivity. But necessarily different people will give different weighting to different attributes.
The Sheldon scale does have more categories (i.e., numbers, now further calibrated into + and *; and with several third party services adding stickers to add yet more nuance). But I am skeptical that increased nominal granularity corresponds to real distinctions in actual coins that can be reliably and consistently replicated across different issues, years and graders.
Grading provides a useful heuristic but I think the claims of objectivity are as much marketing as science.