I don't mean in every respect, but to me, the film's strength comes from it's building to the climactic concert performance. Of course, not that many artists were at their performance peak as late in the game as Queen at Live Aid, but I think you could apply a similar approach elsewhere. Off the top off my head, you could do a Neil Diamond bio that covers his early years and then ends with the Greek/Hot August Night concerts. You could potentially do something similar for KISS and end it with a show somewhere between '75 and '77. I also think that using the original recordings was essential in BR.