pft. I think TFAF looks fine. I'm glad they put in one song that just passing will a huge challenge to someone like me who has played too much. I dont want to beat every song in the game in one day. I expect to beat TFAF at some point, just not for a while. Its a bonus song, so you dont have to beat it if you dont want to.
Which isnt to say a song can be too hard. If you really want to see some songs that do cross the stupid difficulty line you have to play some crappy customs. Here's a video of Eruption by Van Halen
http://www.youtube.com/watch?v=q9ZNh--IyhQ