Don't get too excited about PureView
WP8 supports only the S4 Plus for now, which in turn supports only 20MP cameras. Of course Nokia can still manage to get better cam quality than the rest (hopefully) but there is no way PureView muscle can be shown off at 20MP.There will be sacrifices made, like digital zoom. Hopefully, they should get low light photography right and with some rough math (5MP *4 pixel oversampling instead of the current 8 MP* 5).
If Nokia manages add its own GPU like on the PureView, it might be possible. But just think about it, based on what we saw from both MS and Nokia, it is highly unlikely that any major changes would be made. Yes, I know Stephen Elop said there will be more differentiation but Pureview is not going to be one of them.