Data can come dynamically from JSON, XML, and SQL.  Without the ability to bind a grid to commonly used structures (like a Newtonsoft JSON, .NET DataTable or Dictionary), this grid has VERY limited use for apps that use modern ways of gathering and managing data (like JSON-Schema).

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
 

Universal combo box.

Add a setter for the AutoCompleteBox's SelectedItem property.

For example, to use different keys than the default arrow keys to switch from day -> month -> year in DatePicker

Enable drag and drop between cells of different rows in the DataGrid for UWP. Or a way we can develop it ourselfs.

When the DataGrid is grouped, show the column headers in the group header and allow for aggregates like Sum

It should be similar like the RealizedItemsVerticalBufferScale, but to work for the horizontal part of the ViewPort.

When you have several series(ScatterLineSeries reported but it happens with others as well) in the RadCartesianChart and you clear the Items of one of them by calling the Clear() method - the line is not redrawn and it shows the old data. 

When using shp and dbf files with ~130MB size, it takes minutes to load the map

The uwp radlistview vertical scrollbar disappears when focus is lost -
I think I need something like 
https://www.telerik.com/forums/listview-width-with-or-without-vertical-scrollbar
 <telerik:RadListView.Commands. ListElement.Scroller.Scrollbar.FillElement.Visibility

But I may be missing something?

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