When you click "New Model" Arc will automatically save a blank model, named "Model" in your toolbox. This would be fine if it deleted when you "Save As", but it doesn't. Instead, how about the first time you hit "Save" in your new model, it prompts you to "Save As"?
This would save deleting tonnes of blank models that I never wanted there in the first place.
Of course, being able to "Save As" at all is a nice change.