I agree that Decorah and the river towns feel more Eastern. The Driftless Area as a whole is basically Wisconsin. Thing is, as soon as you leave that part of the state you might as well be in eastern South Dakota or Nebraska.
I think part of the problem with the argument is if you are talking geography or culture or biology or climate or any other set of factors. Then you have the map, that adds many different regions, as I noted earlier. Iowa is about as central as you can get, so can be tagged onto many regions, while at the same time can have reasons to disqualify it from just as many.
Certain parts and towns in Iowa have different culture and "feel" much different than others, even within the state, some towns and areas "feel" like other areas in the country, many of which is because of culture, heritage, traditions, and even localized topography.
That being said, if you want to look at Iowa as a whole, you still would need to designate what parameters you are talking about, meaning by geography, culture, tradition, natural resources, biology, topography etc.
There probably is no simple answer to the debate it seems.