Key word arguments. And I would consider the pythonic approach to be more pragmatic than anything. The language isn't haughty, it just does what it's told. That being said, you've provided a perfect example of what haughty looks like.
It’s kind of a penny wise and pound foolish approach. Arguably it’s not python’s fault, but that’s a poor consolation for folks who have to deal with these messes.
I haven't written numerical code in Go but I am skeptical it will be as maintainable without operators. The lack of a particular feature does not in itself make code more maintainable.
I can't speak to metaclasses, since I have never had to maintain code using them. In my experience they are pretty rare.
I've been writing Python and Go extensively for the last 10 and 5 years respectively. I really recommend giving Go a shot; you can pick it up in an afternoon and it really complements Python well since it excels at a lot of Python's weaknesses (parallelism, performance, static typing, static compilation, dependency managmenet, etc). For example, if I have to write a CLI tool, I almost always use Go since it's so much easier for coworkers to install a single binary than a Python program + dependencies + make sure you have the right version of the interpreter installed.
If Add(x, y) is just as maintainable as x + y, why does Go use operators for the regular numeric types? Why have + at all?