What is Microsoft waiting for providing a decent path API?

I was recently browsing the code source of Managed Extensibility Framework and realized that this future part of .NET 4, full of tricky and advanced ideas, was naively relying on strings to describe files and directories paths. It seems that the version 4 of .NET will miss the need for a descent path API. There is the class System.IO.Path but it is feature limited, full of flaws and pitfalls (to not say bugs) and it fosters users to encode their paths into raw strings. It seems to me that using strings to encode paths is as primitive as using String.IndexOf("<tag>") to parse some XML.