IMAGES INLINE IN POSTS: yes. we need to make some fairly complex changes to the post composer to support this but it is something we want to support for real.
PASTING IMAGES: the problem here is that copied images get passed around as PNGs or TIFFs depending on your OS, not as the original image data. this means that you can end up trying to paste in an absolutely gigantic image, which we can't accept.
we've experimented some with transcoding the image clientside before upload in these cases, but it's always been kind of nasty and slow. we'd like to, but we haven't had the engineering bandwidth to commit to making it happen.
