Agreed to an extent. But what if you want to extend the API to include the same field twice (for example). The semantics of the input object would prevent that.

Agreed to an extent. But what if you want to extend the API to include the same field twice (for example). The semantics of the input object would prevent that. I'm reluctant to spend too much time arguing over a fine point. It could be done one way or the other. I was just addressing aaaaaaaaaaab's question.