I expect offensive improvement, no matter who the OC is, for a couple of reasons:
First, I think our Oline will be better. Maybe top 5 unit again. Getting Fred back will be huge. Looney is solid, but not close to our a healthy Fredbeard. I also expect Williams to be improved and I think Collins will have his best year, as he is in his contract year. Lastly, we will have an entire offseason with an Oline coach that uses the system the guys know. No more experiments with the Oline.
Second, Dak will have an entire offseason to work with Cooper and Gallup. Both of whom could get 1000 yard seasons.
Third, I'm hoping for a at least a few more wrinkles from our new OC. Even just a few new elements will help. IF it's Moore, I would, at very least, expect some of the Boise concepts that gets receivers open by confusing defenses pre-snap. And, I would hope the new OC could play to Daks strengths a bit more.