the biggest thing i noticed, and it was pretty much unavoidable, is that established fans understand who guys like fedor, cro cop, nog, wandy, chuck, randy, etc, etc, are, and that makes their fights more important to them
a newer fan wouldn't know those guys, so a fight like fedor/cro cop, which had huge importance to any longtime mma fan, wouldn't mean much to a new fan, especially since the fight itself is merely good, nothing spectacular.
i could name a bunch of fights that could have made the list, but as its already been said a thousand times, the list is only 25 fights long and mma has hundreds of amazing fights. penn/stevenson, couture/ortiz and anderson/hendo do seem like the odd fights out in the list though. none were anything special in my eyes