Good question/comment ewest! Dang, folks are good on this forum. :-)
I hope everyone else comments as well. I've got two thoughts to add to the discussion.
First, trophy fish indeed are often very unique. It's probably a combination the right genetics and the right setting.
Second, the fisheries profession is just starting to get some "relative growth" standards. So far, there are summaries for walleye, crappies, and channel catfish. It's slower to gain acceptance because growth rates can vary so much from north to south (growing season), while conditions factors did not. High Wr in the nothern states often (not always) means fast growth BY THE STANDARDS OF THAT REGION. The fish in question might actually be growing a lot more slowly than a southern population at a similar Wr.