There's really no way to know how it would have affected the program. On the one hand, as has been mentioned, it might well have solidified Malzahn in his ways, making him less able to adapt to the constantly changing college football landscape. And it assuredly would have raised the expectations of the fan base, particularly since that would have put us just one NC shy of Alabama between 09 and 13. We'd undoubtedly have had more bandwagon fans latch on, fans who would undoubtedly become very loud if we performed the same way in the following three seasons as we have without winning it all in 2013.
On the other hand, it might have made a difference in the way the 2014 team carried themselves. Maybe Nick Marshall doesn't fumble twice in critical situations against Texas A&M, we win that game, and finish the season with confidence (and perhaps another title). It most likely WOULD have made a difference in recruiting, telling every high school football player in America that Auburn is the real deal even without the greatest QB of a generation. Maybe it gets our foot in the door for a couple other QB prospects so we don't have to roll the dice with JF3, and a competent backup saves our season last year.
The butterfly effect that winning the NC in '13 might have had is unknowable, because it didn't happen. Things could have gone in either direction very, very easily. However, as much as it can be positive to reflect on the past to learn from it, it can just as easily be damaging to languish in the what-could-have-been scenarios. Every now and then, I still wonder what might have happened if I had not been in the four wheeler wreck that left me comatose at age 13. Could I have built myself into enough of an athlete that I played college baseball or football? Or maybe I would have learned the work ethic necessary for academics in college, and not had the troubles I did, thus putting my life on a better trajectory than the one I'm on now? ...Or perhaps I would have done well enough in high school with such ease that I grew a big head, and failed spectacularly when I hit the real world, instead of clawing my way through as I have been.
Take my word for it when I say thinking about the what-ifs can be far more detrimental than the actual outcome of that game. There are too many variables at play for anyone except God to understand them all, so at the end of the day, the outcome is simply unknowable, and floundering about with wondering what, why, when, where, or how is ultimately pointless. Gotta keep your eyes forward...and the good news is that there is a great deal of positive potential on the Plains right now. What happens if we win it all THIS season? Does 2013 then become just a near miss in a powerhouse program's beginning of dominance? Do we reach that pinnacle of success where even the bammers of the world are forced to recognize they share the state with a truly formidable foe? Again, right now, that is unknowable, and getting too far ahead of ourselves can be just as detrimental as living in the past (where have you heard that before?). Still, if you want to think about possibilities, I would suggest that you focus on those of the present and the future, because the past isn't going to change whether we like it or not.