I'm the maintainer of a third-party library (gmpy) that would be impacted by this and I'm definately in favor of this change. With ever increasing amounts of memory becoming standard in computers, more users will encounter performance issues with large dictionaries. I see 3.2 as the version of Python 3.x that gains wide-spread use. Regardless of the timing of a stable ABI, it's popularity will make it more difficult change the hash size in the future.