I'm not so sure that I want it to happen so much as I think it would fit - and I know this was mentioned in here before, but I simply can't remember which user mentioned it (if you remind me, I will gladly give credit). In Rurouni Kenshin, the villain tricks the hero into thinking that he's brutally killed his love interest, leaving a fake corpse behind. In this case, if Obito managed to see that Sakura is Naruto's Rin, he might target her as others have speculated in order to try and make Naruto understand his pain, and become like him (as he predicted that he would already). He could leave behind a fake corpse of Sakura or it could simply be genjutsu - either way, Naruto thinks she's dead as do the readers and he falls into despair - this would be a great opportunity for Naruto to prove that he is better, stronger than Obito in that he can mentally overcome the grief of Sakura's passing (except without her actually dying). It'll turn out that in the end, Obito couldn't actually bring himself to kill her for real since she reminded him so much of Rin, thus revealing that she was never dead in the first place. This way, Naruto can experience the same pain as Obito and overcome it in order to successfully TnJ him, without having to sacrifice Sakura's life.
Or something along those lines anyway - I would prefer an alternative that gives Sakura a bit more of an active role (in RK, the love interest was kidnaped and stowed away with the villain on an island while everyone else thought she was dead, and she tried to escape several times - I think she also connected some emotionally with the villain IRRC).
this is better than than the idea that was better than my idea .