any coach whose QB completes 20 of 25 (80%) is going to naturally feel compelled to throw the ball more as it is working great! But typically when teams complete 80% it is because, as in west coast offenses normally, there are many short passes, much like runs which should high percentage completions. IMO.
Not all coaches agree that 'balance' of about half run and half pass is the ideal or desired or optimum amoung. I believe a team must be excellent in running and at least good in passing to be successful (defined as winning about 75% or more of their games consistantly). I would expect that statistically speaking, the winningest teams in history have run the ball more than they have passed it, particularly in numbers of plays but more than likely in actual net yardage. Note: sack yards lost should be deducted from passing yards not rushing yards to be a true analysis). IMO
I think the balance that most coaches are looking for are total yards being 50/50 not total plays.
Not really. When Riley looks for balance, he's looking for play calling balance. Inherently, a typical pass plays are going to produce more yards than a typical run play, so a team will have to call a lot of run plays, or their running game would have to be awesome to be 50-50 in terms of yardage, and not play calls.
Also, I am going to call BS on WCO QB's/teams completing 80% of passes. Wouldn't that be some type of record, and that's certainly not typical.
EDIT: Here are the records for career passing percentages in NCAA history. 70% is the tops.
http://www.sports-reference.com/cfb/leaders/pass-cmp-pct-player-career.html