IA and CO, not ARK or LA was the key to the majority and having not acted on immigration reform through the Congress, not executively, we would have say a different result.
Immigration reform would not have helped in IA. A poll in 2013 by I think either SurveyUSA or PPP said that a plurality of Iowans 46-30 oppose a path to legalization. In fact the poll said that of the four biggest questions (immigration, Obamacare, the shutdown and one other one, maybe Keystone) the voters of IA sided with Republicans on all of them except the Gov't shutdown. The seeds of potential Republican victory in Iowa were there a year ago and the campaign merely played out in a way that allowed them to be capitalized on. ALso there is no demographic differential in IA since the state is so monolithic, save for age and even there Iowa is one of the states where young people are leaving.
The Republicans could do very well in Iowa going forward if they grew a brain.