Three of Texas Tech's "average at best" quarterbacks under Leach were B.J. Symons, Kliff Kingsbury, and Graham Harrell. All 3 spent some time in the NFL, although none achieved much there. I believe Harrell may still be in the league. All 3 won the Sammy Baugh Trophy, which is an award given to the nation's top passer for the year by the Columbus, Ohio Touchdown Club. Other winners have been John Elway, Danny Wuerfel, Ryan Leaf, Landry Jones, and Steve Young.I find the assertion that a spread needs a "superior" qb as absurd. Texas Tech under Leach and Hawaii under Jones never had superior qb's. Their qb's were average at best, but the scheme made them look phenomenal
Symons set the NCAA record of 5,833 yards in a season, Kingsbury was AP Offensive Player of the Year, 9th in Heisman voting, unanimous All Big 12, and completed 67% of his passes for over 5,000 yards in his final season with 45 TD's and only 13 INT's. In 2008, Harrell set the NCAA career TD pass record.
If Leach had only had a qb that was more than "average at best."