Agreed. This feature is sorely needed, and would be extremely easy to add. I believe that Hubspot is deliberately dragging their feet on it, so as to sell more of their CMS module. However, even with their CMS module, there are still holes in our reporting because of other externally hosted pages that we want to be part of a campaign (all traffic, not just UTM tagged traffic).
I understand that this would have to be limited to pages with the Hubspot tracking code installed.