Minnesota proved decent defending the run last year ... and Purdue was a much improved team last year. Minnesota will be contending with a new QB ... but a substantial hunk of their rushing game returns. Purdue will be better on O ... but likely will be rebuilding on D. Both Brohm and Fleck are quality coaches who own the advantage on Frost that they're already a year into implementing their vision for their respective programs.
Is it not a little arrogant to assume that Nebraska owns any sort of advantage over those 2 teams? As much as you might wish to dismiss the fact ... Minnesota DID pummel the Huskers. Furthermore, defeating Purdue required last-minute heroics.
I'll agree with you that Northwestern's home-field advantage is no advantage ... but that also doesn't change the fact that Northwestern, as a program, is currently well ahead of the Huskers. More importantly, Frost intends on re-establishing the Husker rushing game ... and Northwestern has proven quite capable of defending the run.
As for the Huskers having a chance against Iowa ... I'm not enough of a fool to guarantee an Iowa victory ... however, I am willing to prognosticate that the odds obviously favor Iowa in the match-up. First and foremost, the Hawks will have already faced teams that feature formidable odd-front defenses .... defenses that likely will put the Husker D to shame. Thus, given that Iowa will have a smart, battle-tested QB finishing his 2nd year of starting ... I'd say that it is safe to say that Iowa ought to own multiple significant advantages in the game.
Also, have you done your homework on Troy and Colorado? Troy's head coach appears to be an up-and-comer in the field ... and the primary thing counting against Troy in the game against the Huskers is that they'll be featuring a new QB. Over the past 2 years, Colorado has seemed to make significant gains ... although they didn't fare quite so well last year with their new DC.
Lastly, you rightly point out that Iowa went from 4-8 to 8-4 in the transition from 2012 to 2013. However, part of why Iowa went 4-8 in the first place was because they had all new schemes on O ... and also they got hit pretty hard by injuries that season too. Last time I checked, the Huskers are breaking in all new schemes on both O and D .... so even if the transitions are smooth ... what happens to the Huskers if a key player goes down to injury? Let's say you guys are all primed for Martinez to start ... but given that it's a run-first O ... and he's a mobile QB ... what happens if he goes down to injury?