A perspective about Iowa....
Iowa caucuses are dominated by religious social conservatives who go nowhere in New Hampshire. That means a Trump victory against polls will be all the more dramatic. He gets to frame his victory as the people vs. the dishonest media/establishment and their BS polls. The media will go unhinged and into pandemonium. If he wins Iowa, there is no stopping Trump. He rolls into NH, South Carolina, SEC. Game Over. He wins. Keeping expectations in check for Trump in Iowa is to his advantage.
It also takes A LOT OF HEAT off of Trump. With being the front runner, Cruz is going to face major scrutiny like never before. (We already see it here with people QUESTIONING Cruz eligibility!)Trump has prospered taking more incoming than anyone else for the last 6 months. Carson wilted under the heat. Now it is Cruz's challenge. Super PACS and GOPe forces will now run attack ads at Cruz instead of Trump to blunt his momentum so he doesn't run away with Iowa. They fear attacking Trump will only move more of his base to Cruz.
The key to winning Iowa is to peak at the end and turn out your voters. Listen to what Chuck Laudner, Trump's Iowa campaign manager, says about his organization. He knows what he is doing. Trump has a database of many, many tens of thousands of voters who have signed pledge cards. Trump is getting crowds to his rallies in the thousands in counties where in 2012 only a few hundred people turned out to vote for the winner.
Basically, if Trump turns out the majority of his support he wins. It's all about organization. He has the votes to win. The question is do they turn out? I think if they show up for 3 hour rallies. They'll show up for a 3 hour caucus.