Thank you for providing this idea. Could you clarify what exactly you're looking to achieve with this idea. We're working on some changes to support 320px width publish to web reports so they look good on a small phone. Some more details on your idea will help us understand if this is what you're looking for or if it's something else entirely.
In our continued quest to improve slicers, we added a preview of a numeric range slicer. You can read about it in our blog post: https://powerbi.microsoft.com/en-us/blog/power-bi-desktop-march-feature-summary/#rangeSlicer
Still leaving the idea as started, as we are still working our way through many of the other slicer related features requested here. Keep the feedback coming!
We have a custom visual that allows much more capabilities than the built-in slicer. It provides many formatting properties that make it a charm to use.
You can find it here:
Let us know if this is along the lines of what you need or how we can enhance it.
Have you taken a look at our report embedding APIs: http://blogs.msdn.com/b/powerbidev/archive/2015/09/23/power-bi-api-updates-roundup.aspx ? Those will work in an ASP.NET MVC app. Let us know more details on what you'd like 'MVC' support to look like.