I can only give as assessment by the volume of games I have watched over the years. I have followed college football for 68 years and have observed this phenomenom with teams. A balanced attacked seems to be the best if you have the horses for it. A system using more passing than rushing appears to favor a team with less quantity of the better athletes in their fold. A team with an abundance of great linemen and good backs often win big with the rushing approach. At one time, the Big Ten was dominant with the big linemen and running game.
However, this was also in an era when the South did not recruit black players and the great backs were going north to play football. Some of the Southern teams had great teams with great passing attacks during that time.
This next item has been debated many times. A good team that relies mostly on a passing attack will often get beaten by a team relies heavily on the rush against them. The oddity also exists that a superior team who uses the rush extensively often gets beaten by a good passing team. The debate centers around everyday practice at the schools. Some say that the practices have nothing to do with this because the scout squad runs the system of the opposing team. However, the oddity has continued ever since I started following college football. It still appears that a team that uses the passing extensively will often get beaten by a good rushing team, and vice versa.
The other caveat is that a team that relies to heavily on passing will not win national championships, while a team that relies to heavily on the run will not win national championships. It is generally the well balanced team that is the big winner, but a team that does not have the talent to have a balanced attack must also make a huge effort to establish some effective system of rushing or passing to counter that weakness. This is normally where an extremely smart coach earns his money by adapting his system to his talent and getting the most out of it in an effort to have some simblance of both types of attack.
I admired Bobby Dodd for his genius in adaptation, and I admire a present coach in his genius to use this approach, Peterson of Boise State and now Washington State.