Years have past ;-) not really but I think this question has been asked many Times' before.
The forms previewer crash all the time. It could be seen more of a compile:designer that breaks as soon as you start adding codebehind stuff.
We need a designer for Xaml not css? I think the web guys gonna stick to other tools anyways
The live previewer very nice idea, same thing doesn't work yet.
I just need BLEND with a Visual state manager. where is the backning from the Microsoft team that dream up stuff like the Blend tools :-)