Ugg. Sometimes I feel like I'm taking crazy pills when I'm in this thread. We have developed and maintain literally hundreds of web services that work in the way you describe. That's not the point.
The point is that there are many common business applications that require local and shared databases for local caching and reporting purposes. Classic examples are Outlook and all of apps in the Dynamics product line.
Why do we have to regress so much with WinRT? Really? A code contract is necessary just to do a copy and paste of data between two apps? I know you are saying this is primarily for tablets today. But as I said from the start, the Build talks repeatedly refer to WinRT as the future. Maybe this "future" is a few versions out. Regardless, there's no getting around that Windows 8 has made it more difficult to deploy .NET applications to the desktop.
Does anyone else find it ironic that these are called "Modern" apps and the insanely powerful ones are referred to as "Legacy"?