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.
Add the ability to display hierarchical content within the DataGrid
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.
Port RadWindow control to Windows Universal
Ability to view and print report documents
A docking control similar to what is available in UI for Silverlight.
Make the Grid universal.
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.
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.
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!
A color picker that can be used for both in Windows 8.1 and Windows Phone 8.1 apps.
Make RadDiagnostics Universal control.
Port TimeSpanPicker to Windows Universal