Just like components have override capabilities, it would be helpful to have an override option on dynamic pages.
This goes a little further than field overrides like in components, though. What's needed is the ability to add sections and elements without affecting the dynamic page template.
My organization is large, and we have many departments. Each department is a collection item and they all utilize their page. Each department also has certain content that doesn't fit the template or another collection that could be referenced.
That said, it seems like template overrides may be the strongest solution.