[emulord]

I don't think a strict "100 hardest songs" is a good idea.

My idea for a tier list is a couple songs that stress each type of skill in FFR at each difficulty 8-13. This is a fuzzy limit. There may be a few songs in the list that are less, like a "1 or fewer on 100 bar blackout" being worth 1 TP. If the list is good and short, pro's wont mind PA'ing those few easy songs to boost their TP. Then also noobs can have a few TPs and it allows easier classifications of worse players.
5 difficulties * 9 types of skill * 2 songs per difficulty = 90 songs. Similar number of songs, but more comprehensive.

The skills being Blue notes/Background, stream, endurance, jazzlike and confusing rhythm, jumpstream, jumps/triples/quads, jackhammers, rolls/burst, antiskill (token songs).
So for example,
Blue: Lethal Injection, Uber Rave, Marissa Stole the Precious thing, Flight of the bumblebee...
Stream: Purple, Monstrous Turtles, Vertex Beta, Strangeprogram, Reality
Jumpstream: Seven, Exciting Hyper Highspeed Star, Kidney Stone
Quads: Turkish March, Adventures of Lolo
Skill: Nanairopanda v2, OMGWTFT0KEN...
...