Jeff McAffer explains how will be split into more plugins to better support OSGI. This will be done without breaking existing code.
org.eclipse.core.common - some common base support classes like IStatus, etc. We'll look to take into account the JFace uses here as well as other. This will NOT be a dumping ground.
org.eclipse.equinox.registry - the extension registry mechanism
org.eclipse.core.jobs - job support
org.eclipse.core.preferences - preferneces support
org.eclipse.core.contenttypes - content types
org.eclipse.core.runtime - the original runtime layer with things like Platform, Plugin, ...
It will require and reexport all of the above plugins. Make this optional if possible.