I am an Auburn Grad and have watched every game this year and in prevoius years. I have two comments about Fairley.
1) he played sparingly last year and was a beast when he was in there. Auburn fans wondered why he wasn't getting more playing time. So as to the one year wonder comments, I say not really. If you look at tackles for loss, sack etc, based on last year and compare it to his playing time I would guess he would have the same stats if you project them out.
2) As far as a dirty player, not so fast. There are no rules in college that protect the QB like the NFL. So driving the QB to the ground is legal. Also if you are continuely getting choped blocked (i.e GA game) if you get to the QB wouldn't you make sure he goes down hard? He has only been penalized once for a late hit that I can remember, maybe twice, not bad for a guy who is getting to the QB and making plays.
Also a good NT like Kyle would allow Fairley to have less double teams.