The silverlight SDK contained many of the features missing from silverlight: A menu control, a validation summary control,etc. Our silverlight projects made heavy use of them.

A way to preserve changes made to generated javascript files. You might want to look at some of the older code generation systems to see how this can be done, but typically with markup code to define sections of the file that should not be overwritten. If users want to move the code to pure javascript, this enables the intermediate step of having some code ported while other code is not.

I tried it today an there was almost nothing I could do! even BeginAnimation is not supported!!! I tried to make a Border Brush with Gradient but nothing happend! do something about it please. I think you should mostly focus on xaml!

Many of the request here relates to this, but in general I feel there's currently insufficient .NET Types and Framework Classes support. Ideally should be 90%+ coverage

TransformGroup is a missing type, which I use everywhere in my silverlight projects, adding that would make this usable.

For many elements that are supported by CSHTML5, the support is not complete; one or more members are highlight as "not found on {type}" in the XAML editor. For example [Binding] does not support [StringFormat] property. Similarly [LinearGradientBrush] does not support [SpreadMethod]. Please ensure that you support all of the properties for the elements that you claim to be supported.

Enable development and compilation on Apple Macs

Currently the routed events don't behave like routed events in WPF
No Handled property for example

WriteableBitmapEx is a popular set of speed boosting apis.

in WPF is is unmanaged... in Silverlight is is managed code

XAML preview basic interactivity: click on certain Rendered XAML object (UI select) and go to selected object XAML code line (sounds incredible easy for CSHTML5 creatros)

http://jevgenijpankov.heliocode.com/articles/FloatingWindow.aspx

FloatingWindow works perfect in my Silverlight-Framework since 4 years in combination of MVVM Light Toolkit and the GalaSoft.MvvmLight.Messaging class from

http://mvvmlight.codeplex.com/

background: it takes a lot of time to download 'standard' CSHTML5 libraries.

it should be a HUGE speed up to cash (e.g. store to client local isolated storage) the standard 'CSHTML5' libraries like CSharpXamlForHtml5.js (2.6 MB), JSIL.Core.js (0.3MB), etc...

some numbers: it takes 5 - 10 sec to download an empty CSHTML5 web site because of the above mentioned standard js libraries.

controlled Input type to number, text, e-mail, phone, date, datetime, month, etc, like in HTML5:

<input type="number" name="quantity" min="1" max="5">

It would be cool to have some ORM

NetHttpBindings is websocket based, and so we can set bidirectional communications with callbacks from server. A very frequent requisite for a web app.
BasicHttpBinding doesn't support the bidirectional communications required for having the client to reacts to server side messages.
This woul be very useful for chat, games, etc.
And substantially needed for my project :)

support for File.WriteAllText and the other File.Write methods