I'm not sure what the point is.
The real advancements by the companies are coming at the coverstock level.
As far as using old cores, why not? Judging from what I see on a weekly basis during leagues, the old balls still work fine.
Apparently they work good enough for just about all the companies to go back to releasing balls with the basic light bulb/"pear" shape core.
They all boil down to the same basic shapes anyway. The companies can change the density to manipulate the numbers.
Would you feel better if they took that same core and carved a few grooves down the side?
As far as the Nighthawk, AMF did a re-release (solid and pearl) a few years back...I think it was 2007.