docs(ngController): rephrased the description for clarity

src/ng/directive/ngController.js

@@ -5,15 +5,16 @@
  * @name ng.directive:ngController
  *
  * @description
- * The `ngController` directive assigns behavior to a scope. This is a key aspect of how angular
+ * The `ngController` directive attaches a controller class to the view. This is a key aspect of how angular
  * supports the principles behind the Model-View-Controller design pattern.
  *
  * MVC components in angular:
  *
- * * Model — The Model is data in scope properties; scopes are attached to the DOM.
- * * View — The template (HTML with data bindings) is rendered into the View.
- * * Controller — The `ngController` directive specifies a Controller class; the class has
- *   methods that typically express the business logic behind the application.
+ * * Model — The Model is scope properties; scopes are attached to DOM where scope properties
+ *   are accessed through bindings.
+ * * View — The template (HTML with data bindings) that is rendered into the View.
+ * * Controller — The `ngController` directive specifies a Controller class; the class contains business
+ *   logic behind the application to decorate the scope with functions and values
  *
  * Note that an alternative way to define controllers is via the {@link ng.$route $route} service.
  *