I've thought about this for a while - the whole flashback with Rin is weirdly unsatisfying, on two levels.
First - it has always bothered me in past chapters Rin's statements about "I'm watching you." "You can't hide anything from me." "Don't try to hide your wounds from me." In Obito's story, there is never a time where he is shown hiding things, or feeling guilty about hiding them. There is no burden that he bears like Naruto with the Kyuubi. Obito seems like a fairly well-adjusted kid with two parents and a home, and who has a crush and some jealousy issues. Nothing crazy or weird. No obvious inner turmoil. So why does Rin feel the need to make this big "I'm watching you" speech? Not that Rin wouldn't be that type of caring girl...just that it doesn't fit with Obito's storyline. He isn't the type of kid who needs some extra special help from being 'watched over.' (Or did Rin already recognize he was budding psychopath?!
)
Second - the flashback with Rin in this chapter when she states "I'm watching you" begs the question from Obito: "So, um...what did you think of everything I've done...for you...?" It puts it front and center that Rin was watching him. But in the moment of some kind of guilt, where she should weigh in and not be just a figurehead that he put on a pedestal and made his muse for destruction, she just says, "Eh, it's all water under the bridge." It's friggin crazy!
Obito annihilates people left and right in the name of love, but when Rin finally is given a voice in the manga, Obito's whole responsibility is just swept away. How can she be truly watching him and not abhor everything that he's done, everything that he's turned into?
I'll tell you how: by framing it in a flashback that happens in the distant past. The Obito that comes for resolution is still an untainted child. The Rin that accepts him is still a child. Neither of them admit the very grown-up things he did. Showing Obito as a child in his final death moments shows how really warped he is. He doesn't seem himself as a grown up. Therefore how could he be responsible for these awful things? I can't think of any other character reverting back to their childhood in their final moments of lucidity.
It would have made more sense to have grown-up Obito reconnect with Rin in that nether-space that Kakashi met his father (remember, at a campfire or something?). Then Obito would have been given a true absolution from Rin, the one he held above all others, rather than Naruto, a person he only saw as a weapon up until only a few short chapters ago. That would have been a much more satisfying ending.
Anyway, regardless of the sappy ending, Obito still equals a Hitler-esque figure for me in this story. So, wrapping it up this way, with Obito reverting to his childhood self-image and getting a pass from his 12-year-old crush, seems no less hollow than Hitler getting one to absolve all his terrible deeds.
/end rant