Microsoft"s XAML has a lot of people worried. Its advantage is to bring the ease of web page authoring and scripting into writing .NET application user interfaces. This makes immense sense. We have a desperate need for decent user interfaces, and the place where a large body of UI designers and programmers live and work at the moment is in web pages.
The web is on its way out for UI-based applications. What users need is a tool suited for the job, not a crippled interface shoehorned into a browser. XForms is not going to save the day here: it will improve the situation for web-based data collection, but it won"t keep large scale client projects inside the browser. XAML"s benefit is to bring the web page design culture into the richer world of native UI. Good-looking native user interfaces are key, along with integration with the rest of the operating environment. OS X has demonstrated this loudly and clearly. Even for networked applications, web services have given programmers more freedom to move the UI back into native widget sets while still retaining some of the advantages of the web application.