Being past the merge window, the Linux 3.7-rc2 kernel just brings a lot of fixes for regressions and other outstanding bugs. Most of the work for -rc2 involves addressing fallout issues from the UAPI include file re-organization. There's also various DRM driver fixes, USB driver updates, and other scattered changes throughout.
The release announcement for this second release candidate of the Linux 3.7 kernel can be viewed at LKML.org.
Some of the most interesting changes for the Linux 3.7 kernel are covered in this article.