Hiro couldn't save Charlie's life, I don't see him playing around in time to try and save Jackie's. If only because it would really cheapen the events in Homecoming, and as much as I enjoyed that episode, I don't want to watch it happen again and again until it gets done "right".
"Do-overs" are too dangerous to do with brute force direct intervention (like trying to save Charlie), they only work when done with precision like giving Peter vague clues and hints.
I think that's what this is leading to - Hiro can't interfere himself, but he can get others to do so.
QUOTE (Mister Fate @ Nov 22 2006, 03:33 PM)

once again for the masses...
"subway hiro" knew that he wasnt able to save the cheerleader in fact, none of them knew anything about saving the cheerleader in his time line.
looking back on his past, he must have figured out where the turning point laid. he knew then that he wasn't where hne needed to be, and couldn't be. so, he went back in time, inlisted peteres help because, apparently he knew peter in his timeline to be capable of this feat.
why hirop couldn 't be there obviously has somehtig to do with the fact that he travelled back in time. charlie still dies in this time line becuase HRG has a picture of her corpse. but i theorize that she dies a few weeks earlier, or abouts. since thats about when the waitress said that hiro disappeared out of her life. there for.. hiro must be preoccupied with another task at the time of homecoming.
I pretty much agree with this.
If Hiro was in the company of several witnesses, then Charlie could have died a couple weeks earlier.
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Jackie isn't the one they had to save.
If Future Hiro didn't come back, Peter wouldn't have known about "save the cheerleader, save the world", wouldn't have told Mohinder about that, who told Eden, who told HRG, therefore he brought in Isaac and confirmed it was Claire and she was going to be attacked on Homecoming.
Without that, he wouldn't have grounded Claire, but she and Jackie would still have ended up alone in the girl's locker room. Sylar would still have attacked Jackie there, thrown Claire to the wall, see her healing and chase her. But this time, without Future Hiro's interference, Peter wouldn't have been there to help and Sylar would have caught her and killed her.
Peter saving Claire is the change, no one could have saved Jackie without being in the girls locker room, which would have drawn some questioning stares at the very least and likely a police call.
They needed to save Claire because her healing ability will be very important later on to stopping a disaster.