PEP 398 lists some of the features that may be included in 3.3:
PEP candidates:
PEP 362: Function Signature Object
PEP 380: Syntax for Delegating to a Subgenerator
PEP 382: Namespace Packages
PEP 393: Flexible String Representation
PEP 395: Module Aliasing
PEP 397: Python launcher for Windows
PEP 3143: Standard daemon process library
PEP 3151: Reworking the OS and IO exception hierarchy
(Note that they are not yet accepted and even if they are, they may not be completed on time for Python 3.3.)
Other planned large-scale changes:
Addition of the "packaging" module, replacing "distutils"
Implementing __import__ using importlib
Email version 6
A standard event-loop interface (PEP by Jim Fulton pending)
Adding the faulthandler module.
Breaking out standard library and docs in separate repos?
A PEP on supplementing C modules with equivalent Python modules?