It's a bummer that when creating a dynamic content that the Original content is required because that are scenarios where if the Rule is not met, we want nothing to show. For instance, we have an email that lists out 3 possible changes to their monthly autoship, and they are passed to me as flags. I do a dynamic content on each one and if that rule is met then I want to show a line of text as a bullet point. But if that rule is not met, then I don't wan t to show anything. To get around it, I had to add this HTML to the Original content:
<span style="display: none;"> </span>
It would be a nice feature NOT to have that section required. Just sayin.