While technically possible, this would be difficult to accomplish in general. Some faculty would try to move to the web, others would use remote services; others, especially departments and colleges; would build their own solutions; some would ferment rebellion. Students would probably support this rebellion - the SGA's Academic Affairs Committee is working on a project that would provide (require) online resources for all courses.
On the positive side, this is an easy and inexpensive upgrade, and though there would be some cost in moving from AIX to an different platform, the conversion would be relatively smooth. Integration with LDAP would solve the largest single issue with WebCT today - password maintenence.
On the negative side, "classroom in a box" problems remain; course material is available only to students registered "in" that class. I.e. since it's not a big change, it's not a great leap forward.
Blackboard would provide a good measure of the current functionality of WebCT, and would probably attract additional faculty for whom WebCT is too arcane. It would also integrate with LDAP.
On the negative side, several courses would lose an important functionality ("quiz" discipline) and not gain any additional functionality. There would be fair hefty conversion cost as webct courses were retooled. This is a larger change than 1a, and would be something of a large step backward.
On the plus side, Vista offer a real upgrade to the WebCT architecture by placing course "content" in an external database separate from the coure "transaction" database. This encourages resusability of course material; WebCT itself is a participant in the MIT Open Knowledge (Standards) Initiative. Vista is also perceived as somewhat easier to use than earlier versions.
This increased power will come at an increase cost, and although the approach is correct, it may not be the best solution for UVM. The content management system approach is being looked at from many perspectives - the digital library perspective of ENCompass (which will provide course archives storage), the Oracle collaborative suite, which provides an enterprise wide document management approach indpendent of platform, etc.