> I think it would also help if calling a method via super() didn't allow
> positional arguments.

That's absurd, *except* for __init__(), where it could make sense depending on the style of cooperation used.  But not enough to enforce this in the language; in Py3k you will be able to enforce this on a per-class basis.

> Having two mixins with the same method name and
> without a common parent class is just not sane.

Right.  This is a cornerstone of cooperative multiple inheritance that sometimes seems to be forgotten; there is a big difference between defining a method and extending a method, and only extending methods can make super calls.

The __init__ case is an exception, because there's no requirement that a subclass have a signature compatible with the superclass (if you don't get this, read up on constructors in C++ or Java).