Hi,
The ArcGIS Runtime SDK for WPF already has 3D analysis capabilities provided by Geoprocessing. We are planning to add 3D visualization functionality in the future across all the ArcGIS native appplications/SDKs. Some demonstrations of this were shown at the recent User Conference in San Diego, in an application developed for the Mac OSx platform I believe. For WPF we hope to be able to add 3D visualization sometime during the next year but it's not possible to be more specific at this time.
Cheers
Mike