I believe this was already planned once, but I wanna see it actually come to reality; basically, it's a mod that says, if you don't get a 300 on a note, you fail. So basically, if you get a 100 or lower, you fail the song. It's like sudden death, but more strict. Like this idea?
Duplicate: http://osu.ppy.sh/forum/viewtopic.php?p=896001#p896001
Duplicate: http://osu.ppy.sh/forum/viewtopic.php?p=896001#p896001