A TreeView/TreeMenu-like control would be great to have. Currently there is no easy way to realize tree-like structures, like the menu that the official Mail App has.

Port the Windows Phone ImageEditor to WinRT.

http://www.telerik.com/products/windows-phone/overview/all-controls/image-editor.aspx

Provide a universal JumpList similar to the Windows Phone JumpList.

Implement Scheduler control

A DataStorage that can be used for both in Windows 8.1 and Windows Phone 8.1 apps.

Port RadWindow control to Windows Universal

I think that will be a very good feature. Just create a gantt control available over this platform. A gantt control like UI for Silverlight will be a fantastic one.

Add the ability to display hierarchical content within the DataGrid

Ability to view and print report documents

Make RadDiagnostics Universal control.

A color picker that can be used for both in Windows 8.1 and Windows Phone 8.1 apps.

I've ported over my app from Windows Phone 7/8, but now I've found myself at a loss of functionality without your textboxes available as universal controls. RadTextBox, RadPasswordBox, and RadNumericUpDown are all controls that would be fantastic if they could be ported over to Universal.

Thanks!

The RichTextEdit from Microsoft is still not a perfect port, and missing many functionality.

And only a few .NET vendor that has RichTextEdit control in their Windows Phone+WindowsRT suite, Telerik unfortunately not included, :(

Please reclaim your crown as most complete Windows Store Suite back by adding RichTextEdit control for Windows Universal.

Make the Grid universal.

A docking control similar to what is available in UI for Silverlight.

Provide a tabstrip control that allows users to display content on tabs.

 - Tab content could use virtualization to avoid extra rendering
 - Follow themes from Telerik
 

Provide ability to export the data displayed in the grid to excel.

Please, add the RadMap control to your plan