It is an unfortunate reality that API's developed and pushed to the public must be unchanged to avoid applications such as Control Panels, Billing Systems and so much more from breaking.
Our only options to make things perfect and keep things moving forward on the latest technologies are to introduce NEW methods. We will be introducing JSON API's in the future.
We have Enterprise organizations that will be using 1.0 versions of our API's for their entire lifetime. Its an ugly reality :)