Tony,

  In MVC, routing is used to determine which controller and action method to call given a specific URL.  If you called http://mysite.com/home/edit it might call the Edit method of the homecontroller.  This is all defined by routes which your application defines in the routemap (this is the same concept used in web services).  In the DNN MVC approach, routes are defined in the module manifest for each modulecontrol.  You can see an example of this for the sample MVC HTML module: <controlSrc>HtmlText/Index.mvc</controlSrc> or <controlSrc>HtmlText/Edit.mvc</controlSrc>. In these examples, the framework will call the Index or Edit action methods on the HtmlTextController depending on which "control" is being rendered.

So, when I say that DNN doesn't give you routing control, I mean that you do not have the same level of control over how routes are defined.  In ASP.Net MVC you have full programmatic control over routes just like you do with the Web Service Framework.  In the DNN MVC Module framework, you have some limited control which largely relies on convention with little ability to override the convention.