The overall performance against Pitt makes me uneasy about the final stretch. I am not worried about Navy (though, the history with them has not been without surprises), but the remaining 4 do give me pause.
Northwestern has shown it can be difficult - just ask MSU. Although it has struggled all year, FSU has sufficient talent (and incentive) to create problems as it did for Miami. Syracuse played Clemson very tough, narrowly lost to Pitt and also has the incentive of taking down ND - plus, that game is close to home for them which may mean sizeable fan support. Finally, USC seems to be improving and will have plenty of time to get ready (likewise, with lots of incentive to spoil the party after last year).
Looking at the inability to sustain any running game, Book's drop off in overall performance (sorry, the 70% completion number masks some serious issues), and that kickoff redux return to open the second half, I get a tad nervous. Tthe fact Book also took some hits, doesn't help calm me. Book may prove the Pitt game was only a bump in the road and return to the form of weeks 4-6, and all will end well. But,If he gets a concussion or other injury, I don't see BW getting the Irish to 12-0.
Some of my concerns are focused on the OLine which needs to get much better, especially at adjusting to unexpected tactics of opposing defenses (for which responsibility, perhaps unfortunately, lies with the coaching staff).
My other concerns center around the QB situation. First, which Book will be showing up down the stretch? The confident one of a couple of weeks ago, or the less steady one that played against Pitt? If he gets injured or does not revert to his earlier form, who will step in? There were reasons why Book replaced BW, and is not clear those reasons should not be expected to remain valid. And, since he has seen only a few minutes of action, Jurkovec would need to be the second coming of Montana to step in and take the team to the promised land.
ND has benefitted from a perfect storm of upsets wreaking havoc on the rankings. But, some tough sledding remains to get to the Final 4, and there is lots of work yet to do to take advantage of the situation.