It would be cool if it were at least easier to put a kendo style modal within a kendo window that covers the content of the window. 
An example: Confirmation of action, if a user clicks to close the window it would be nice if a modal could be displayed, covering only the window content until the user confirms or cancels.

Build a Kendo Pie chart with long label names in the legend.
Hover the chart close to the legend - if the area around the chart is too crowded with legend labels the tooltips (supposed to be displayed in that area) are actually placed very far from the chart, leaving the chart container.
Maybe it would be beneficial to replace the absolutely positioned tooltip <div> with an svg representation.

Now that the Kindle Fire devices are flying off the virtual shelves, it would be cool to add Silk support for Kindle Fire devices. Not sure how you do that or if it's even possible... just putting it out there.

We have built some really cool stuff with Kendo UI Mobile.  We want to present or Apps on regular web pages with non-HTML5 browsers.  Maybe in an IFRAME like Facebook.  We need graceful degradation functionality.  Any interest?

I need to be able to bind similar to:

  <%= Html.Telerik().TreeView()
                .Name("TreeView")
                .DragAndDrop(settings => settings
                    .DropTargets(".drop-container")
                )
                .ClientEvents(events => events
                    .OnNodeDrop("onNodeDrop")
                )
                .BindTo(Model, mappings =>
                {
                    mappings.For<Employee>(binding => binding
                            .ItemDataBound((item, employee) =>
                            {
                                item.Text = String.Format("{0} {1}", employee.FirstName, employee.LastName);
                                item.ImageUrl = Url.Content("~/Content/TreeView/Common/contact.png");
                                item.Expanded = true;
                            })
                            .Children(employee => employee.Employees));
                })
                .HtmlAttributes(new { @class = "t-group" })
        %>


and have the functionality of sorting, filtering

It would be nice if you added an option to actually use combobox in mvvm scenario.
http://www.kendoui.com/forums/ui/combobox/combobox-mvvm-binding-entire-object-instead-of-object-value-mvvm-bug.aspx

Like:  sortable: { mode: "multiple", max: 2 }. When the 3rd one is sorted it unsorts the first.

I have seen a few different samples on how to implement a dynamic skin chooser for Kendo UI Web, but I think this would be a great UI control to be added to the suite itself.  None of the code samples I have found are simply drop in and use, but require slight modifications.

Have the opportunity during the reporting grid columns to add or hide visible property. This then avoids calling the function hideColumn.

By default the column is visible.

Allow actionsheet to be databound to a DataSource

Add support for the HTML 5 data-* so we can access the Kendo API in this elegant and unobtrusive way.

Example, Kendo's date picker could be called this way something like this:

<input type="text" class="myClass" data-kendo-date="true" data-format="dd/MM/yyy" data-min-date="13/12/2013" />

This feature will help a lot then you need to show user a text values but send number values of cells to a server.

Release a guide similar to the jQuery UI one which shows the best practices to develop our own "kendo ui conform" widgets and allow and document the code reuse - like globalization - from our own widgets.

When you click on a tab in a TabStrip, the expand animation shrinks the content area's height to zero, then expands it to the height of the new tab. This isn't bad, but gives a "bounce" effect to the control, which can be offputting (I've had complaints about it from users).

If would be nice if you could animate it from its current height directly to the new height, without shrinking to zero in between. That would be a much nicer effect.

We are using the kendo dropdown widget and noticed that the performance degrades quite drastically if it contains more than 100 items. Can you investigate performance improvements even for larger item sets?

Find Node or search mode

Add client-side filter method that automatically updates the filter menu options (dropdowns and values) according to the filters described in the filter expression.

I'm reposting this as a bug since currently when multiple windows are created, the zIndex never gets adjusted like in telerik.window.js hence it is impossible to have dynamically created windows without having to fix the zIndex manually for each new window. And once you adjust the zIndex on one window, it always stays on top.

Original post with comments:

http://kendo.uservoice.com/forums/127393-kendo-ui-beta-feedback/category/31821-bugs

I'd love to be able to do fractions in the NumericTextBox

...fractions are numbers too! ;)