The KitKat version of GoogleHome.apk is already beyond bitrot; it's "an empty shell that forwards all requests to the [proprietary Google] search app" (which manages the home screen in KitKat), per ArsTechnica:
This leaves it unclear what you get for a launcher with an AOSP build of KitKat, but it certainly is drifting farther from the official Android experience.
You can (and I have) fetch the new Launcher from AOSP, compile it and run it very easily as a separate application. The Google Experience Launcher is a closed source Google app based on this which integrates Google Now.
http://arstechnica.com/gadgets/2013/11/google-just-pulled-a-...
This leaves it unclear what you get for a launcher with an AOSP build of KitKat, but it certainly is drifting farther from the official Android experience.