I’ve seen good and bad hickory with both thick and thin rings. I think the early/late wood ratio is more important, like PatM said. There was a swamp where used to cut hickory and the outer growth rings would be all early wood, over 50%, and very thin. But deeper in the wood the rings were still thin but without much early wood and that stuff was great.
I don’t know if there’s anything to this but I feel like the good hickory I’ve used has a slightly stronger color to it, more yellow and pink.