Add a new feature to easily export/import current grid settings, such as the column size, page index, page size, column index, etc. This is useful for saving/restoring individual user's custom grid.

This can be added to other databound widgets, too, such as the ListView.

Based on this thread that I created: http://www.kendoui.com/forums/ui/grid/save-load-grid-settings.aspx

It would be great to have file manager support in addition to the image manager for the HTML editor. Some sort of way to upload resources, organize them, crop (for images), and ultimately select from a picker to be included in the HTML markup. 

It would be great if users could hide or show columns. Typically this would be done by a popup with on the right a list of all displayed columns, on the left a list of all hidden columns. Users move columns to the right or left by using arrows, double-click or drag-drop. In the same pop-up they should be able to change the order of the columns.

Create light-weight Diagram visualization control/wrapper.It may integrate with Telerik's Silverlight/WPF RadDiagram framework.
http://www.telerik.com/products/silverlight/controls/diagrams.aspx

We need a pager beyond the grid guys. Did I miss this one? Honestly Kendo Widgets would be good enough so we could build our own components for things like this.

DataSource should be more feature rich. I consider following features a must in order to be able to develop complex UI's without the current pain

- Multimple models definition
- Associations between models
   - BelongsTo
   - HasMany
- Lazy load of associations!
- Allow use a REST approach for associations (send updates over a HasMany association to a service)
- Allow send the complete object

- Association validations
   - Unique
   - Exists
   - Min/Max number of elements

Knockout.js is a de-facto standard.
It would be nice if KendoUI supported Knockout so developers could use just one paradigm of bindings/observables/templates/etc.

I was really looking forward to using Kendo UI Mobile, but the one control that was critical for my idea was a slider, which is missing from the Mobile package and, apparently, not even on the roadmap.

In the long term, SPA features are absolutely necessary, especially when it comes to HTML5 apps (also in regard to Windows 8 WinRT or upshot.js - a key part of the forthcoming Microsoft RIA stack). 

A good SPA addresses the following issues:

- real permalinks
- page titles
- a working back button that fully degrades 
- different data states like http://bit.ly/zpybmz
- client side caching
- asynchronous updates/communication
- ...what else? (please add if I missed something)

Example SPA: http://pjax.heroku.com/ 

Similar functionality to the jQuery UI sortable feature.

The beta text editor is looking good and has an option to insert images via url.
However for most end users they will need a simple image upload.

The kendoupload means you already have much of the required functionality, it just needs to upload the image and return the url.

Also options such as adding title, alt, resizing and alignment will be good.

We currently use ckeditor and until the advanced image options are matched will not be able to move this over to kendo.

Add the ability to reorder columns (and their data) within the Kendo UI grid. This would preferably be handled through drag and drop. 

I've implemented a large list of options in a listview that I expect a user to select one from.
I am detecting the selection by the 'click' event, but this fires even when the list is scrolled.

Add spell checker to the new Rich Text Editor similar to the other Telerik Editors.

It would be nice if you could add a disabled state for k-button.  That way, we don't have to hide the buttons from the users to force them to enter some information before clicking a button.

Support for spline chart type

 For example the grid with filtering turned on appends multiple div and form elements to the body element. It is impossible to clean these up which is very important in a single page application. Every widget should have a destroy method which is capable of removing any associated events and elements it was responsible for creating.

Could I suggest a better integration with Phonegap like:

- desktop utility app to package Kendo UI Mobile app into installable packages for iOS, Androind etc..

To produce the bugs:

Edit a cell value then the red mark appeared.
 Edit another, the mark is on both cells.
 Click on the first cell, not modify just click the 3rd cell, and the modified mark is disappeared. ( but the cell still modified from the zero state )

Edit a cell value then the red mark appeared.
 Insert a new row, and the mark is disappeared too.

Sorry my English is bad.

István

Why don't add useful tips for paging?

just like:
http://demos.telerik.com/aspnet-mvc/Grid/Paging?theme=vista

or jqgrid