For all of Python's great and convenient features, one goal remains out of reach: Python apps running on the CPython reference interpreter and using multiple CPU cores in parallel.
This has long been one of Python's biggest stumbling blocks, especially since all of the workarounds are clumsy. The urgency to find a long-term solution to the issue is growing, notably as core counts on processors continue to ramp up (see Intel's 24-core behemoth).