They are added back to IntelliJ. It is sort of a weird development process. Android Studio is a fork of IntelliJ, so it always runs a bit behind. At the moment Studio is branched off IntelliJ 13.3, not 14. Meanwhile, IntelliJ pulls in the Android Studio stuff into their plugin a bit after Studio releases it.

If you want the latest and greatest IntelliJ features, use IntelliJ + Android Plugin. If you want the latest and greatest Android specific features, use Android Studio.

If you have a paid license of IntelliJ, you are probably better off with IntelliJ + Android plugin.

Most of those features are already available in IDEA 14, others will trickle through very soon (usually it's couple of weeks difference or so).

ADT plugin is being abandoned.