What is Booster's destiny?

A storyline that's been unanswered since Millennium.

Originally the Manhunters were defeated in part because Booster Gold went undercover as a traitor. But his efforts weren't appreciated as the other heroes believed he did betray them and only helped out to save his own skin. After Harbinger told J'onn that Booster was one of the descendants of the Chosen he got the JLI together to bring Booster back to the team.

The connection to the Chosen who would later be called the New Guardians probably isn't canon anymore. The series based on the latter title talked a great deal about it's title characters breeding to pass on their "superior genes" but it was a flawed premise. See, a number of them didn't seem like they could or would reproduce because:

1. Some of them didn't seem to have the, uh, parts. Ram seemed to mostly be a giant computer and Betty was just a head that floated.
2. One member was homosexual and while that doesn't rule out the possibility of children I have no idea if this was addressed in the series. 
3. One or more members (I haven't read the series) contracted an STD via a vampire they fought.

I've seen a little talk about who Booster could have been related to and well I'm just going to throw out a suggestion that I see many overlook: Harbinger.

She was one of the Chosen but I get the impression many overlooked her and see her more as a mentor than member. Anyway I didn't just pick her because she's blond. From a narrative POV I love the idea of Booster not just having a son that knows all this history but also coming from such a person. Harbinger's real name is also Lyla Michaels which would be a nice touch. Now you might be saying, "But Booster already has Daniel and Rose" but that doesn't mean Lyla still couldn't be related to him.

Her kid could get together with Daniel and Rose 's or further down the line. She could even be related to him on his maternal side. But yeah she died in old canon but then again so did Booster.

Anyway fast forward to the Johns/Katz series where we're told Booster has to hide his ID or he'll be killed. ...Except the Time Stealers know who he is and won't kill him. Mr. Mind wanted them to get Booster to quit. Not even Black Beetle will go back and prevent him from being born. Booster has to be important enough, to do something great enough that not even the villains are willing to prevent it. During Convergence old Booster tries to pass the buck of some great mission to the New 52 version (which doesn't make sense now) so what is it?

It can't be his role as a Time Master in general as the Time Stealers tried to get him to quit. It can't be Rip as they don't know who Rip is. It has to be something he does that no one else can that benefits everyone. Otherwise the TS would have no reason for letting him live.