Here's one quick way to test if your application has properly segregated itself between the Model, View, and Controller roles: is your app skinnable? My experience is that designers don't understand loops or any kind of state. They do understand templates with holes in them. Everybody understands mail merge. And if you say, "Apply the bold template to this hole," they kind of get that, too. So separating model and view addresses this very important practical problem of how to have designers work with coders. The other problem is there is no way to do multiple site skins properly if you don't have proper separation of concerns. If you are doing code generation or sites with different skins on them, there is no way to properly make a new skin by simply copying and pasting the old skin and changing it. If you have the view and the logic together, when you make a copy of the view you copy the logic as well. That breaks one of our primary rules as developers: have only one place to change anything.