okay, why the hell would she WANT to stay there? the only reason she isn't leaving is because she has no idea what she's missing. she was invited to the hakurei shrine, but she never took up on that offer (unless she was shown there at the ending. I've never gotten to that) and why on earth would she respect the one who's kept her locked up all her life? yeah, they're family, but Remilia seems to keep her locked up 'cause of her powers... well, I think the flandre thing has hit a dead end.
I've got another subject to discuss: Hakurei's god. who is she (could be a he, but I doubt it, so I'll keep saying she), and why hasn't she shown her face like Kanako? After stage 1 of Touhou 10, Reimu says "I hope my shrine's god is stronger" or something to that effect. At first I thought it was Mima, but then I noticed that she wrecked the shring in Touhou 2. Then I thought that it could be Reimu, but then I realized that she wouldn't refer to herself in third person like that. also, she's human. so here's my theory: the shrine has no god, and Reimu is gathering faith for herself to become a god! why else would she try to snuff out Moriya shrine when it appeared?