ClientTemplateId is fine when you are using kendo templates, but in our case we use handlebars templates, and in order to tell a listview that we need to do something horrible like 

<script type="text/x-kendo/tmpl" id="TPStrengthTemplate"> 
	#= Handlebars.templates.TPStrength(data) #
</script>

asside from interop, the script tag is untenable in large applications, as it may force us to create TONS of superfious script tags (some with the same id in the case of repeating partial views). Especially when template precompiling is a 'best practice' for client templating (hence our use of handlebars)

instead there should just be an option to specify a client handler pointing to Handlebars.templates.TPStrength

The documentation wrongly says that the grid will perform all server operations of paging, sorting, grouping, and aggregating whether bound to an iQueryable interface or a DataTable (http://docs.telerik.com/kendo-ui/getting-started/using-kendo-with/aspnet-mvc/helpers/grid/faq).

It turns out, after an extensive support ticket, that the documentation is plainly wrong. I have been told that only the COUNT() aggregate is supported when doing server side operations and bound to a Grid.

My request is that this gap in functionality should be fixed so that server operations work for both iQueryable datasources and DataTables.

Ability to write c# code or use model property value instead of just bool value to hide or show a cell(.hidden())

Currently on WidgetBuilderBase there is an HtmlAttributes method that clears any current HTML attributes before adding the new ones. It would be good if there was a separate method called maybe AddAttributes (or something similar) that would allow the addition of HTML attributes without clearing any existing ones.

it would be nice Editor -> DocumentBrowser & MediaBrowser  same RadEditor

The MVC Grid uses the MVC EditorTemplates and currently does not support setting a JavaScript function name for the column's "editor" property.
Please consider adding the ability to set the javascript name for the column's editor.

http://www.kendoui.com/forums/kendo-ui-complete-for-asp-net-mvc/grid/binding-to-custom-editor-for-a-grid-column-i-e-drop-down-list.aspx 

instead of using the text parameter to apply filter in server side, use the filter parameter of the DataSourceRequest/DataSourceResult object for the comboBox.

The Upgrade Wizard should provide an option to only update currently used skins rather than adding all skins each time a project is upgraded.

I'd like to suggest a TagCloud just like the one in Telerik Ajax offering.

When using the LoadContentFrom() in a tab inside a Tabstrip, the tab content does not get loaded until it become visible. 
Please consider making the Kendo Window behave like the TabStrip when a window use the LoadContentFrom() method, loading the content only when it become visible.