Just to clarify... the "preview" release is not intended as a full, ready-to-migrate release. We mentioned up front that there were missing components and that the docs weren't complete, etc. etc. The goal is simply to show what kinds of changes there are in the new architecture and gather feedback on what's there currently. Once the first feature-complete beta is available, along with the migration guide and compatibility layer that are currently being worked on, the migration effort will go much better.