I do think the offense will be better. Partially because it can't be much worse. But, more that my eyes did see spurts of competency out of the offense last year, they just could not maintain drives. I think the OL will be more consistent and the running game will be better with bigger backs who don't lose yards. Goodson was a very talented back, but he lost yards too often, and Iowa's offense was not good enough to overcome 2nd and 13. Petras has weapons and an arm and I think will be much more effective with a running game that is consistent and downhill.
If Iowa can literally be average on offense. Seriously, like 60th in the country, this team could be really good.