It's about balance to me, and I think what a coach can do on O, D and ST depends on the play of each other.
As an extreme example, I think of the Bills when they relentlessly ran the no huddle offense like no other team. Their defense is what made that possible.
Anyway, I think it's about two things really. The first is you find the identity of both your offense and defense, what makes them special, what do they do the best and how do they force their opposition to adjust on a more consistent basis, and then they find balance to that.
Then I think you have to look at how to financially make that happen, which to me points to the draft. And this is where I really think Fisher and Snead have excelled. Regardless of whether everyone agrees with their choices, and I definitely have not agreed with every choice to date, they've traded down and up to fill their needs reducing their need to overpay for UFA help as quickly as a team in their situation can while giving the fans something they want to watch and the owner something to support.