In short, WPF matured after VS 2008, so the developer has a lot of crap since he very soon completed the development cycle for Visual Studio.
In VS 2010, however, the improved constructor is significant (as well as the WPF application in general ... many of the components of VS 2010 are WPF themselves), but I would stick with Blend for now. I personally use Blend to design Visual Studio for code.
Soon VS 2010 / WPF 4 will appear:
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