We are very aware of that. But...
This is a service pack feature. And in a service pack, as a rule, we do not upgrade the Active Directory schema, so we couldn't add a per user mechanism configurable through GPO.
That said, we did add a way to set the policy XML on each user (read the last paragraph of the post), it's an all-or-nothing deal, so it's not quite perfect, but that's all we could do given our AD restrictions.
The next version of Exchange will have those settings on the user object and be manageable through GPO (or any other policy mechanism that can deal with AD settings). The debate on whether or not to create a Mobile Device AD object is still on-going, but the settings will be configurable, at least, at the user level.
Microsoft
