I agree with Chris M, there is a need for single point administration for user accounts. I recall at one point someone mentioned that the decision to remove this feature was due to customer feedback. I was at Exchange Connections 2006 and most of the other admins I spoke with would prefer to have a single point of management, albeit it was only a dozen or so. For meduim (<1000 users) size companies such as mine this is going to create an addtional load on our already overburdened IT staff.
Also I was told that Exmerge will be not supported under Exchange 2007, can you provide addtional details and also maybe blog about the cmdlets that will replace the functionality of Exmerge.