We've made some updates to the BizTalk Server Roadmap that will hopefully shed some light on what the plans are for the product with the pending R2 release as well as future versions of the product. BizTalk Server 2006 R2 will feature a number of updates over the initial 2006 release including rich integration with Windows Communication Foundation and Windows Workflow Foundation through the WCF Adapter SDK and new Business Activity Monitoring (BAM) interceptors for WCF and WF which will enable you to leverage BAM functionality in non-BizTalk applications, updated support for the 2007 Office System (which includes an update adapter for SharePoint Server), and comprehensive RFID support.
In addition to all the new capabilities introduced in BizTalk Server 2006 R2, the roadmap also provides a "sneak peak" in to the future strategy of BizTalk Server and the investments that are being made. Head on over to the roadmap and check it out.