It looks like this talk will be a GREAT discussion about the evolution and limitations of IIS from the perspective of the IIS team.

http://msevents.microsoft.com/CUI/EventDetail.aspx?EventID=1032243866&Culture=en-US

From the site:

Description:This session reviews the evolution of Internet Information Services (IIS) to its current iteration -- version 6.0 -- and how IIS 6.0 has measured up to customer expectations since its release in April 2003. IIS 6.0 built on a new architecture, but this architecture has a few areas where improvements can be built-in. The system administration capabilities include a new Edit-While-Running feature but the metabase has a difficult to read XML schema. The scalability lacks a clear path above 8 processors and IIS needs to optimize performance in this area. Up to, and including all of these, IIS 6.0 is a new and revolutionary product. This session will cover the delta between what was delivered and what has been learned and help you our customer know the areas where Microsoft needs to build for future IIS versions.