>For example: you can't assign the result of an "if" statement. Why? Because it's a SyntaxError, no real reason. There is even an "ifExp" in the language grammar, but that's only for inline ifs.

Do you mean something like a ternary operator? You can certainly do: x='foo' if condition else 'bar'.

In fact you can even do multiple assigments: (x,y) = ('foo1','foo2') if condition else ('foo3', 'foo4')

where 'Foo' may also be a function call.

>I think people feel like it's unpythonic and instead pollute the namespace with singleton classes that only have one method.

There's a few pycon talks on "a single method class should not be a class" but I'd say that's the single responsibility principle at its purest along with the community needing to move to more lightweight structures like namedtuples.