I really like what you've done so far and I think you're very close to the top if not already there in terms of being an HTML5 UI leader. The one thing your data visualization set is missing is a map. A simple map to show chloropleth data, basic paths etc is well within your reach and would round out your DataViz offering.

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

React uses a declarative paradigm that makes it easier to reason about a JavaScript application. React computes the minimal set of changes necessary to keep your DOM up-to-date. 

Kendo UI seems not to have such an update feature. But since React works with most libraries and frameworks, please create an example app with React or make a blog post about how to use React together with Kendo UI Web.

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. 

I would really like to see a Gauge control similar to what is available through the Telerik Silverlight controls.

It would be nice to use the Kendo UI Editor to manipulate and style tables, add/remove rows and columns, just like MS Word does.
Together with some friends we discuss this issue and we saw that it is a very important and useful feature for the most end-users, because they are comfortable working with MS Word and they notice that fault when using web applications.

Would be nice with some sort of table support in the rich text editor. Normally we need a very stripped down RTE since it only represents a part of a page (a block), so the bells and whistles of tinymce are a bit overkill.

However it seems that even though it might be difficult to use in an RTE due to complex UI, we often get questions regarding how to insert a table into a text. Not a complex table, but just a simple table with maybe a class, some th and td's.

It would be really nice if we could stop integrating tinymce and just stick to one library, with a little more beefier RTE in Kendo UI. :)

Element to chose color. That is usefull forvisual  template bulders and CSS editors and more. I am curently needing this UI

Would be nice to have a way to easily configure columns to be fixed (position and width), like a checkbox column to select rows.

This kind of column need to have fixed width and position (cannot be reordable).

But, KendoUI could has also a native support for rows selection, allowing us to just turn on this feature that could have a lot of sub-features: Remember selected rows by page, mark/unmark all, custom options in the column menu to massive mark, and so on.

Just test the basic usage sample on the web site.
If you are able to set all splitters as you wish, you are the king!
All other controls work as expected.

A ListBox widget with the following core features: skinnable, drag and drop to transfer items, ajax binding, support for templates.

My marketing department has requested a specific look for a chart. The Moc up image is http://i.imgur.com/Z2hKaei.jpg in order to achive what they are asking I need the Labels to work in the Bullet Charts. 

It would also be great if you could add a label to the Target as pictured in the image. 

Thank you for  adding Excel-like filter. This is what we wait for a long time.

Could you please add textbox to excel-like filter?
So, if there are too many options in filter i would like to search for option i need. (Kind of filtration in excel-like filter)

Example: http://imgur.com/SIdHmSb

I use Durandal/Knockout and Breeze for my PhoneGap mobile App. Kendo Mobile is one of the best looking CSS libraries but cannot work with Durandal.

This sums it up -  http://stackoverflow.com/questions/17758991/where-to-init-kendo-mobile-application-in-durandal/17786286?noredirect=1#17786286

The Editor widget would be configurable to support (GitHub Flavored) Markdown syntax and would optionally display a live preview of the text.

I am put off using KendoUI because of the limiting nature of theming and styling the controls especially the sprites

They don't scale well, can't be coloured and are hard to replace without lots of css editing. 

It will be nice to have keyboard support for Grid with Virtualization of remote data (odata) and virtual scrolling enabled.

As it can depicted in your demo:
KendoUI meets Wakanda, http://wakanda.spirit.de:8081/

if you try to press key down, the grid is not scrolling down when you bypass the limit of visible rows. In addition, if you scroll down using mouse (scrollbar), if you try to press key up then the grid is not scrolling up. Also, keyboard keys page up / down, home, end and in general keyboard functionality is not supported. 

Despite of keyboard support, your demo is impressive!

Regards.

Thomas

See http://www.highcharts.com/demo/line-basic for a good example of  Client-side Chart Export