It certainly isn't my favorite song, but I'd like to see Here we go!! because it has yet to appear in any Second Vision game (excluding when it was a BGM in G4U). Other songs that might get in would be the other SP DLC songs (Kimi wa Melody, Matane, LOBM). Also, where is THE IDOLM@STER? Sure it was DLC in Shiny TV, but why was it not standard in OFA?
Most of all (but it'd extremely unlikely), I'd like to see the Dearly Stars and Jupiter trios actually take the stage. It's really awful that they can't be used in any capacity, and it puts all 6 of their image songs firmly into the "Not Happening" category.
I remember thinking before OFA was released that if they continued quintet guests (like Ryuuguu Komachi) that they might include 876PRO as possible guests. I guess that's why it hurts to see songs 876PRO has sung as DLC, particularly quintets, because Scamco has the recordings and the models but sees Dearly Stars as dead.