MVC 3 included improvements over MVC 2 such as additional view engines, additional objects for sharing data between views and controllers, and better support for features like jQuery and dependency injection. Specifically, MVC 3 supported the Razor and Web Forms view engines while MVC 2 only supported Web Forms. Additionally, MVC 3 provided objects like TempData, ViewData, and ViewBag for sharing data while MVC 2 only included TempData and ViewData. Support was also improved in MVC 3 for features like jQuery and dependency injection.