I don’t buy that she almost pulled the trigger before. She reluctantly took the pistol out of her purse, at Peter’s urging, but Peter said “oops, nevermind” before she had to face the horror of really shooting her uncle.
And that’s what it was, to her – a horror. It was a horrible burden to put on a 15-year old, and everybody (Noah, Peter, Nathan, Claire) knew that. Really, the better option would’ve been for Peter to have shot himself, or borrowed Hiro’s nagamaki and eaten it, but I’m not really sure that he could’ve mustered the guts to do that.
In the end, only Noah could’ve been trusted to do the deed. Even Nathan – one of the more strong-willed characters on the show – chose to die with Peter rather than to live having killed his brother. It’s a bit strange to complain that not-quite-adult Claire didn’t accomplish something that none of the adults could bring themselves to do, either.
Although I’ve complained about Niki, it wasn’t about that. Spandex would have, indeed, been dumb. If just for how stupid it looks in real life (something the X-Men movies got right, IMO).
My complaint about Niki was that her entire story arc was about taking control of her life again, after having given up control to her father’s abuse, to Jessica, to Linderman, to DL, and basically to everybody but herself. She finally took charge of her life and started acting on her own in this episode – as evidenced by her being able to access her super-strength now.
And then, in the final scene, she takes one decisive action – and then meekly listens to Peter (whom she doesn’t know from Adam) to go back and sit on the sidelines like an obedient little girl. All that long, rather dull story arc, and she’s back to being the girl who does what other people want her to do, not the woman who does what is right.
It would’ve made no difference in the narrative of this episode had she clobbered Sylar, and then been TK’d by him across the plaza like he’d been doing to everybody else (even when stabbed through the chest by Hiro). Yet, that would not have been completely contrary to the character development that Niki had been given.