[snip plenty of wordy arguments about Python, DSLs, misunderstandings, etc, with almost no code, and going nowhere in particular]
I'm not a Python guru, I'm not even a professional programmer, worse than that I've never even been a CS student. But I think, humbly, that this thread is much too preoccupied with personal/philosophical opinions about the aesthetics of Python and not enough with *how* to make Python work assuming that statements become expressions.
IMHO if we try to work out how, we will come to the conclusion that it would make it a horrible mess. But we can only establish this if we give it a try, and in the process we might learn something useful. And who knows, we might even discover that Python was really meant to be a functional language! After all, this list is called python-ideas.
Sorry for the noise.