I guess that most people that use Visual Studio had my same reaction when they created their first ASP.NET MVC project: where did the Design View end up?
I think they are working on that as a feature for Expression Blend 5 Developer Preview .
They clearly recognise the issue of designing JS in the designer so I suspect they realise the same applies to some designers working on MVC applications.
I was told by someone from Microsoft "I think in Blend for HTML, using interactive mode, you would probably be just fine with designing MVC or MVVM patterns"
Also check out Visual Studio Page Inspector it looks like it will do what is needed
Now use WebEssentials with BrowserLink in VS2013 or up