In response to your questions:
1) Does this assume Windows Mobile 6 on the client side?
Answer: These changes are part of Exchange ActiveSync protocol version 12.1. The current version of Windows Mobile (6.0) Support Exchange ActiveSync protocol version 12.0.
2) Any change to the rather goofy practice that the remote wipe asks the thief that stole your device if it is OK to wipe the device?
Answer: The issue you are referring to actually has to deal with whether there is a set of policies applied to that device. If the device has policies applied to it (any policies) then you will not be prompted. If your organization does not enforce any policies then a user will be prompted before a wipe. This is because the wipe request is sent down with a blank policy.