Linus began the 3.4-rc4 announcement with, "Things looked fairly calm for a while, but that certainly changed yesterday. I think either people time their pulls for the -rc releases too, or it's just a matter of many developers actually having a somewhat normal Mon-Fri workweek these days and they close the week by sending my their pull request." More than half of the changes for the Linux 3.4-rc4 release landed just yesterday.
While this uneases Linus, especially as he will be offline for a couple of days due to scuba diving related activities, he does believe that the final 3.4 release is still on track.
As far as Linux 3.4 changes go, see this article and the other Linux 3.4 kernel coverage for more details on what's new with this forthcoming release.