[zahlman]

>which breaks in the fringe case an exception that derives from BaseException (enforced by interpreter) but not from Exception is thrown.

For many users, in many cases, this would be fixing the code rather than breaking it.

Forcing people to write either `except BaseException:` or `except Exception:` means forcing them to think about which one they actually mean. This is a good thing, just like the enforcement of proper separation between bytes and text is a good thing.