Is there supposed to be Intellisense for the new
Make sure you add
"Microsoft.AspNet.Tooling.Razor": "1.0.0-rc1-final" to your project.json dependencies.
You also need to add
@addTagHelper "*, Microsoft.AspNet.Mvc.TagHelpers" to your _ViewImports.cshtml to make the tag helpers available in al your views.
You can get more information at aspnet 5 documentation page