A CMS would be useful for pages like "Shipping and Returns", "Conditions Of Use" etc. However, I don't think a fully featured CMS is necessary (or at least a priority).
What about, like we have SettingManager.GetSettingValue, we have a ContentManager with GetContent(string Name).
Then we have a generic control e.g. <nopCommerce:ContentArea ID="ctrlContentArea" runat="Server" ContentType="Content.ShippingAndReturns"/>
Then all we need is an area in administration to add new content types using fckeditor for the html.
This way, nopCommerce can be shipped with the default pages like Shipping and returns mapped to a specific content type. This gives users the ability to modify the content of these pages without changing the source.
Then, if users do require a new physical page to be added, it would be quite easy to add a new content control to the page and map this to a newly created Content type.
The ContentManager class could be quite simple as we only need a couple of fields and methods to add/update/insert/delete.
Just a thought.
Ben