I don't want a specific philosophy, per se. I think Diaco is a smart guy (sometimes too smart for his own good but I digress)... I don't buy the argument that "he's a defensive guy he can't do offense". Defense is the yang to the offense's yin, if you will. There isn't one without the other. He should be very skilled at analyzing a defense and determining the weaknesses. I think he alluded to this concept when he was first introduced as coach. How are they set up? What are their tendencies? This should feed in to the game plan to say : based on our offensive capabilities.... when we see X, our best chance for yards is Y. Get to the line quickly. Read the D. Have a few plays to choose from. Get the play call in by (whatever aribitrary time left on the play clock) and execute. Make the required adjustments during course of play based on the results.
As noted ad nauseum, I feel Diaco has a very specific, plodding style that he wants to force until he's left with no other alternative. Tl;dr... be proactive and tailor plays/game plans to opponent weaknesses instead of trying to score the bare minimum of points.