IF GD is asked to move on or if he just retires on his own, I think KF will go after the best OC he can find who knows the pro set, stresses the run game with a play action passing attack, which in turn stresses deep throws, seam routes and tight ends, with more screens and some variations in the line blocking scheme. We would see jet sweeps and a very limited number of flat passes to try for some yards after catch. In other words, return to KOK's offense, one with which KF is comfortable. I think he made an honest attempt to blend the KOK scheme with the GD horizontal passing attack, but it was/is a complete disaster.
I do think we will benefit from GD's insistence that we recruit more speed and athleticism at the receiver positions. Now if we can add a couple of premium running backs...
I absolutely do not think he will hire Brian F. as the next OC. The speculation that he is grooming BF for this position has no basis in fact and has become yet another internet myth.
Finally, I am hopeful that GD will be gone and that we can return to an Offense that KF likes...maybe then there is a chance that he will open up the offense. Maybe.