I obviously don't have experience with Python, but the only good thing about the syntax to my eyes is the vertical space savings you gain by doing away with curly braces.
But…that’s not how you format “private” symbols in Python, conventionally; single leading underscore is; double leading is for identifiers you want mangled with classnames, and double leading and trailing is for special methods.
[i*i for i in range(10)] is hardly terse or cryptic.
Python regular expressions are much like regular expressions anywhere else, so you're not really criticising Python there. You might need extra backslashes if you were trying to do them without raw strings (r'\s*' == '\\s*'), but that's hardly unique to Python either.
That‘s not random syntax trivia. It‘s a slice. Pretty generic and straighforward.