My biggest regret over Expression Blend is that it was not released in conjunction with WPF and XAML, at their introduction. My viewpoint is that if anyone has to create or edit any kind of XML (including XAML) by hand, the developers have failed them. (XAML, Ant, XSL-FO... any sort of XML.)
Barring some infrequent situations such as merging branches in source control, or figuring out a damaged XML file.
Related to Expression Blend was SketchFlow, for prototyping that was actually functioning and not merely mock-ups and wire diagrams. It was (is?) an incredible tool for UI designers to make functioning designs.
That was a separate team that created SketchFlow, and it leveraged the power of WPF. (WPF is one of the Microsoft technologies that is best-in-breed in that domain, in my not-so-humble opinion.)
Alas, it appears SketchFlow is a casualty of the changing times. :-(
I think .NET (and Mono) is pretty darn impressive technology. For example, I've had good experiences using Visual Studio for Macintosh (formerly known as Xamarin), and F# on Mono.
FYI: they just released WPF as open source with MIT license (today is full of news both from Microsoft and Google): blogs.windows.com/buildingapps/201...
Wow! I'm utterly shocked and pleased with this news!
I'm not shocked that Microsoft made it open source. I'm shocked that the developers were able to disentangle WPF from its tight coupling OS dependencies.
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