He was athletic enough to play in Bronco's system because Bronco's system hides BYU's deficiency at CB. He was a JC transfer who didn't receive a scholarship offer so he walked on at BYU.
And yes, many teams are playing off today. But not every play for the entire game. Bronco himself said his defensive strategy back then was to prevent shots over the top and allow teams to shoot themselves in the foot because he didn't believe our opponents could execute all the way down the field.
I liked Criddle, but "athletic" and "BYU CB" have rarely been used in the same sentence, ever. And he isn't even on the long list of CBs in terms of athleticism at BYU.