So right out the gate I'm going to give my two cents with the assumption Fish is here next year. It pains me greatly, but at this point here's the way forward as I see it with that given (which I still hope changes but that's neither here nor there).
Fisher needs to get out of his own way on offense, first and foremost. He needs to bring in a LEGIT offensive coordinator and give that guy the power to make staff changes with that side of the ball if needed. Norv Turner is ideal from a Jeff Fisher perspective, simply because he's fielded balanced offenses. And there is nothing wrong with prioritizing a strong run game, btw, as long as you have a coordinator that can balance it with passing the ball.
Now I am sure some will come back with "No way on Norv, game has passed him by, Fish needs to bring in hot young WR coach X, or this guy or that guy," etc, etc. Problem is Fish is on a one year deal, and even hot positional coaches might not want to come in to this sinking ship for one year. Even Martz might not want to, and that's assuming Fish would consider him, which I doubt, as set in his ways as he is.
It might take management twisting his arm to get that done. And it might take Jeff phoning a friend to get a real offensive mind in here, too. If things go that route, my guess is Jeff will call Mike Shanahan, for a couple reasons...
One, he and Mike are good friends. Mike's son will be the belle of the ball for head coaching positions, so sliding in as OC with the Rams to help right the ship might be attractive to him, particularly since he has two critical pieces in the offensive backfield in Goff and Gurley.
Two, the dude straight up knows how to put together a strong run game. He also favors mobile OL in his run scheme, and also might serve as a reclamation force with GRob. The type of OL he likes are often available well into the draft, so adding one or two that route should not be too difficult.
If management leaves Fish to his own devices, he'll probably cut his own throat by promoting from within. In which case I honestly think I'll take a year off from watching football.