Great defense and special teams, along with less than lethal offenses were the trademark of the Tressel era. Yes, there were a few years YSU had rather strong offenses, but for the most part it was great defense, highly efficient special teams, and offenses that did not beat themselves, and then took advantage of things done by the defense and special teams. Scoring after recovering a fumble or an Int... scoring after a great defensive stand, and then having excellent field position as a result of either said defensive stand and/or a play by special teams. Kickers who were highly reliable from 40 yards and in, and who could also make FG's of 40-50 yards if needed.
Look back at all the games YSU won with what would be deemed rather average or even below average offense, over the course of the entire game. Heck, the first NC in 91 was won this way. The offense had 1 solid quarter(the 4th). Defense and special teams kept YSU close enough, and then the offense had that one amazing quarter. In 93, after a few long runs by Smith and Clark, the game was turned over to the defense. And, anyone old enough likely still remembers that huge goal line stand in the 4th quarter of the 17-5 victory.
The 92 semi0final playoff game at UNI. NO OFFENSIVE TD's. YSU stopped UNI 3 and out on the first possession of the game. UNI then punted and Dave Roberts ran the punt back for a TD. Crwod was quickly taken out of the game, without the YSU offense even stepping foot on the field. The rest of the YSU scoring was from 3 Jeff Wilkins FG's... YSU won 16-7.
Semi-Final game in 99 against FAMU. Defense with a huge goal line stand early in 4th quarter when trailing by 12 or 13 pts. FAMU coach had a brain fart which helped, by calling a pass play. Tim Johnson intercepted. All of a sudden, the mood swung in an instant. Offense went down and scored a TD. Defense then held FAMU to a 3 and out. YSU got ball in excellent field position, and offense scored another TD. Defense then held FAMU to another 3 and out, and YSU went on to the NC game.
Those are just 3 games that come to mind. Oh, how about the 97 NC Game... YSU 10 - McNeese State 9 .... YSU had ONE quality drive on offense, which resulted in the game winning TD. And, it came after an INT, from what I remember the only turnover of the game. So, yes, I believe NDSU can win another NC with a great defense, and less than lethal offense.