You don't see it because you are a rabid Iowa fan that can speak intelligently about every player on the roster. But from an outside perspective a team that finished 10th in the conference in KenPom (#71 just ahead of #73 Ohio State) and lost their leading scorer is not going to rate highly by most random neutral observers, especially when there are no super highly rated freshmen or transfers coming in.
It is what it is. If you are an Iowa fan/coach/player it can motivate you. But if you are a basketball journalist that sees Iowa lost Jok and wasn't very good last season it's hard to get terribly excited about moving them up highly in preseason.
Michigan State deserves to be the preseason #1 in the Big Ten next season for obvious reasons. Beyond that, though, is a big jumble of teams that all have lots going for them as well as a question or two. Rutgers, Illinois, Ohio State, and Nebraska would seem to have the bottom 4 on lockdown. #2-#10 is the big tight grouping IMHO.
Personally I'd probably go MSU, Purdue, Michigan, Northwestern, Minnesota, Wisconsin, Iowa, Maryland, Penn State, Indiana, Illinois, Ohio State, Nebraska, Rutgers.