ASP MVC 3 is just released and there is already a roadmap for the next one.
Here is a quick summary of some features that might come with ASP MVC 4.
Recipes are wizard to make some stuff a lot easier.
Like adding a datagrid to your page. You might need a controller, data classes etc.
Recipes will be delivered via Nuget and makes it possible to do this actions without writing code.
Ever tried browsing to a asp mvc site with the default Template?
If you have you might have seen that it isn’t optimized for smartphone or device with smaller screens.
ASP MVC 4 will have an optimized stylesheet for mobile browsing.
It might even include individual layouts, views and scripts (such as jquery mobile)
Razor syntax for HtmlHelpers
Tasksupport for AsyncControllers
It might be possible to bundle js and css files into one file.
This reduces both bandwidth usage and download times, which speeds up the rendering of web pages.
HTML 5 support
For editor and display templates
For the full list of possible features of ASP MVC 4 you can check their site on codeplex.