Rectify all the default variables being passed around

[raghavmecheri]

Feature Request

Description of Problem:

We've taken a fairly risky/bad approach by just resorting to setting function params to arbitrary defaults when they aren't passed in. While this works sometimes, I think we've overused this approach and should really trim parts of it down.

Potential Solutions:

Eliminate optional parameters in any non-public function, and actually throw exceptions when things aren't right, rather than passing None values around