Based on what I've gathered from luncheons and coaches shows and such, I do think the staff is engaged in finding hidden gems--guys with raw talent who fly under the radar. In other words, I wouldn't be surprised if they're intentionally shirking the ranking system in some cases.
But don't fool yourself: If BYU could land a class full of five-star guys, they would. The reality is they can't compete with the big boys for elite recruits, so they have to go through the back door to find excellent players.