I don't think we'd gain anything by that.  Exponentiation is the only operation where you actually need to worry about polar coordinates -- if you look inside the various `opOpAssign` entries you see that they always stick with real + imaginary.  So, you'd probably lose numerical precision on average by storing things in polar form, unless you had a very specific set of requirements for how you wanted to use your complex numbers.

There isn't a `Polar` type, we could add one, but it might be easiest simply to have a function that takes polar coordinates as input, converts them to real + imaginary, and returns a regular `Complex` type.