You could make the argument Luke didn't have the best career at BYU. You can say he wasn't the best blocking running back at BYU (he wasn't asked to block very often)...
...but you can't say he doesn't belong in the top five running backs at BYU. That's asinine. He had by far the best single season of any BYU running back. He was an amazing athlete and much more than a "system" running back. Crowton's system never before or after produced another running back like Luke. It wasn't the system.