With Microsoft's experience delivering various products off of an application server, as well as their extensive experience in remote computing and web delivery there may be some potential for this to really work well. From a tech support standpoint it would be very nice if everytime someone started Outlook it fetched any necessary files, updated itself, and rebuilt after damage automatically the way it can in an application server environment.

As well, given the cost of Outlook, a fee that included annual upgrades to the new version might not be bad.