Hyperlink control like a HTML.
Allow link a file in local machine/network and show dialog do open a file. Just HTML Control.

Prjofessional LOB themes like JetPack really give SL traction. A bit more capital allocation to those with the gift to create quality reusable themes for the SL developer base would be greatly received.

Give us the abliilty to override a combobox (hopefully an autocomplete one) display data when selected an collapsed. Extremely useful for a custom combobox using mulitple columns and you only want to show the user a single column selection when closed / selected. Currently it requires editing in the CoreStyles.cs

In WPF it's possible to set Bindings to be updated immediately when PropertyChanged (i.e. in a TextBox, PasswordBox etc. as user inputs text, without waiting for focus loss).
This feature is very essential when completing forms to be able to RaiseCanExecuteChange of a SaveCommand or other command in the ViewModel telling it that validation has been affected.
Silverlight currently lacks this feature and AFAIK it's not planned to be implemented in SL5 either and that's a shame!

It helps a lot with all the math involved.

Typicall use-cases:
- custom context menu with own commands + "Silverlight" option
- custom/disabled context menu and "Configure Silverlight" button in SL application settings

1-Silverlight UI tablet fluids like iPad
2-Customizable UI by developpers
3-Silverlight App store "which Microsoft says it's a generic word :)"
4-A thin tablet with USB port for external connection that would let us transfers at ease
5-Minimum 120gig
6-WIFI of course
7-Browser with Silverlight plugin for web based Silverlight apps.
8-Cameras
9-Intelligent enough to know that you're using it and it turns on alone and turns off alone if you go away !

For offline SilverLight applications, if we have an option to place icon in Tray Area (it checks for some thing in background), an alert will popup when some action required from user.

This will helpful in many places, like I need to monitor weather of one place for evey 5 minutes & need to generate a pop-up when weather crosses given limit. In this case we can this feature.

I hope that Silverlight 5 can support P2P

Provide API that will enable automated testing on Mac

You can't launch a browser with a URL from OOB app.

the following line works in SL when in the browser but not in OOB.

System.Windows.Browser.HtmlPage. Window.Navigate(new Uri("http://<server>/<resource>"), "_blank")

There is a workaround using the HyperlinkButton but a proper solution is needed.

See also: http://stackoverflow.com/questions/1542563/silverlight-3-out-of-browser-htmlpage-window-navigate and http://mokosh.co.uk/post/2009/10/08/silverlight-oob-open-new-browser-window/

Adobe Air allows developers to access the entire file system. Silverlight needs this if we are expected to be able to write robust desktop applications with it.

Main idea is to allow simple user to install silverlight without any special permission.

The Panorama View in the Metro UI for WinPho 7 is a very nice navigational paradime, that would also translate well to touch enabled web apps. Please include one.

could the default view of Silverlight controls assume the look and feel of the operating system without using styles. ASP.NET controls do and this would help 'blend' (no pun intended) the two 'out of the box'.

It feels ugly to know we still cannot run beautiful silverlight applications in Android, iphone etc etc.

That limits use to think while using silverlight for developing data driven application.