I dunno whether the reason for the lighter touch was that director wasn't deft enough to evoke a deep emotional response, whether she didn't have band permission to go there, or whether it just wasn't that kind of movie. ^^; Based on Cherie Curie's book, executive-produced by Joan Jett, mainly focused on the two of them and opportunistic record producer Kim Fowley. The rest of the band don't even get where-are-they-now blurbs before the ending credits. R and I were discussing how the movie could have fit in more about the other members: I said make it longer (it's just 1hr45min), she said cut out some of the "high" scenes, which after the first couple are all basically the same.
The beginning of this movie is really good: Joan buying the leather jacket and kissing her best friend; Curie dressed up like Bowie for the school talent show; the two of them trading quips and bonding over stories of alcoholic parents. It has a kind of specificity of time, place, and personality to it. There's a strong feminist message in just how much grief they are given for wanting to imitate their idols and play rock music. After the drugs come in, the plot becomes a lot more generic...though their concert in Japan, immortalized on television, is faithfully reproduced down the the stage antics. Maybe they just can't remember anything else that happened during that time?
The acting is good, especially Kristin Stewart's. She's really grounded and honorable as Joan, and manages to convey some of the musician's charisma. There was an ad for Eclipse before the movie; I could and still can imagine hordes of 15 year old Twilight fans coming to see Runaways for Kristin, and then developing huge crushes on her-as-Joan-Jett. ^^ That is, if they can manage to sneak into the theater (the movie is rated R). Honestly you forget that she is Kristin Stewart.
While I was watching, I kept going over what-ifs. What if Cherie's sister had come with them on the first tour? Or cut her hair to match Cherie's the first time she came home between tours, so that there wasn't that obvious visual cue marking them as different? What if she'd come along on the second tour? Would Cherie have stayed grounded and stayed in the band? But then she was saving her sister from that life, wasn't she... especially from the attentions of Fowley, who doesn't treat any of the other members the way he treats Cherie. With the rest of the band it's insults that could pass as tough love, but Cherie is belittled, objectified, leered at, made to pose provocatively, etc etc etc. She has a special place in his heart - or some other place - it seems.
Speaking of posing, there's a sudden break in Cherie's character after she's covertly featured in a softcore porn spread. It's like she's been violated by more than just the camera. Before she's defiant, confident, she has attitude. After she's deflated and passive. R said, "It's funny, it's like they chose her for her style and attitude and then proceeded to beat all that out of her." It's obvious enough that you wonder what happened to her offstage between Acts One and Two. Was it the Press? The Fans? Their tour manager? Unsubtle acting?
Overall, an interesting film. Its major weakness, which I see most of the reviewers mention, is that it really needed to decide which of the two of them to follow, Joan or Cherie, after the split; which is like saying that it needed to decide which narrative arc to follow, the bottoming-out-then-finding-your-center arc (Cherie) or the picking-yourself-up-and-kicking-the-slac
I have some other thoughts, but this is disjointed enough as it is. XD; Comments welcome!
Though her relationship with Joan is written as the one positive, non-exploitative relationship in her band life, which makes a really nice change from the EVIL LESBIANS you see in so many films.
 Except for the one where Dakota channels washed-up Hollywood starlet to play Cherie doped up on her father's painkillers at the grocery store. That was priceless.
 The only time you're reminded that she's not Joan Jett is her "rebirth" scene in a bathtub near the end, when the director takes away the clothing, makeup, hair, and body language, and just leaves a wet Kristin Stewart. Wryyyy!