The MVC framework is already capable of automatically bundling, minifying and caching on the fly. EWL could probably easily utilize this, drastically improving performance on the client-side.
AND it’s able to process Sass before processing? I’m drooling.
I’m pretty sure that this feature has no actual relationship to MVC. It’s just an ASP.NET 4.5 feature. Actually I’d be shocked and disappointed if it was somehow tangled up with MVC.
It appears the package that actually supports this functionality is WebGrease; http://webgrease.codeplex.com/documentation