It's hard to recruit for the type of offense that they run. Top rated recruits just don't want to play in the triple option. You would think most RB's would love to play in it though since they would be the main focal point.
Paul Johnson gets a whole lot out of extremely average at best recruiting. I think GT has a 8-4 season in 2015 and by the time the recruits are seniors GT will win 9-10 games.