'The biggest flaw in the Flash IDE is that it basically encourages bad code, you can bury code in a literally infinite number of places - external files, movie clips, timeline frames, frames within movie clips. It gets ugly very fast. Visual Studio 2008 integrates nicely with Subversion and other version-control systems so your code is organized in a logical way from the beginning, making it easier to update, maintain and share with other developers.'
Oh look I've got silverlight - I'll ignore everything MS has told me over the last 30 years and suddenly become an modern computer programmer.
The reason why we have billions of lines of badly organised code is BECAUSE MS told us that computing could be made easy and without any of the discipline that is so badly needed today.
Just because VS2008 can connect with a non-ms version control system that actually works doesnt mean people are going to do anything useful with it.