AngularJS, which just released 1.0, is gaining a lot of fans (including myself and my developer-friends). There already is an AngularJS adapter for jQueryMobile, and I hope the KendoUI Team will work on an AngularJS adapter for KendoUI very very soon. I think a solid AngularJS adapter implementation will pull my team over to KendoUI for good.

If it is at all possible, please implement drag & drop inside the grid to enable users who need to manually sort items in order of importance (for instance a list of books I they wish to show in certain order).

Maybe CSS3 can do more nice text,textarea,button, but in IE7&8, can not support border-radius,box-shadow,text-shadow, so we must use picture to do this. I want to all the form element seems the same in KendoUI support browsers.
Just like: Uniform,Niceforms,Jquery FormOne,jqTransform,jNice and so on...

Can we make the tabstrip scroll-able instead of wrapping tab items to another line? Let's say I'd like to target both Ipad and iphone and the tabstrip would have 6-7 items. 

http://www.kendoui.com/forums/mobile/tabstrip/tabstrip-wrap.aspx

Although Kendo has fency filters with different operators (StartsWith, Contains) on different columns based on data type, Most business users  like to have excel AutoFilter(Multi select checkbox) where they can choose what companies, countries they want to see

You can see a live demo here at - select company, country or any other column.
http://demos.devexpress.com/MVC/GridView/Filtering

Currently only an array of page size integers can be set in the pageable.pageSizes property. It would be really great to have an option for adding "All" within the dropdown somehow.

Please think the Kendo UI validation farmework not only in terms of client-side validation but also in terms of reporting server-side errors.

A framework that would only provide a way to display a validation error message based on a client-side rule after each related input field would not be very helpful in my opinion.

All errors need to be reported in a consistent way. My preferred option is:
- a message box at the top of a form to display all messages including OK messages and error messages (client-side and server-side).
- higlighted fields with tooltips (not to clutter the form layout) to repeat error messages in context when applicable.

Although the framework built into Kendo UI might only provide client-side validation, please make sure to provide entry points into the UI used to report errors. Alternatively, leave the UI to the developer and provide a simple way to collect all validation error messages on a form.

When you want to add a new item to TreeView you can only set the Text of that item.

Maybe it would be nice to store more data like the id of the new <li> element

Big SPA projects need to have an architecture for the code, some structure. Current examples for SPA are suitable for small apps, so some docs/examples/guidelines for bigger projects would be useful.

Buttons that works like checkbox. First click it is on an highlighted second click it is off

At typical usecase for web applications is to let the user upload and image (portrait, avatar, picutre of real estate etc.) and then resize and crop it to a specific contrain.

An easy widget for handling the cropping and resizing might come handy for many.

There are solution for cropping and also resizing in jquery plugins already, however a successful and pretty combo of the two seems to lack a bit.

Inspiration:
http://deepliquid.com/content/Jcrop.html

Today you can only export JavaScript primitive values - String, Number, Date, Boolean.

http://www.telerik.com/forums/export-grid-to-excel-cells-with-hyperlink

Currently templates are only supported when the DropDownList is in an open state.  Ideally, the DropDownList should have the ability to display a template when in a closed (selected) state as well.

A common use case is to display icons next to the dataTextField.  However in it's current state, when an item is selected the icon is no longer able to be displayed.

I'm using kendo ui for mvc and a control that could be very useful is a captcha for form submission.For sure you can integrate it by using Google reCaptcha in a easy way not only for kendo ui for web but for mvc also.A good idea could be to integrate you own captcha control (for intranet environment, or private internet network ) because reCaptcha only work with a stable internet connection (Google Web Service).

Can we have a theme or feature of all input controls that can support floating labels like in google material design? 

The current material design theme demos do not show example of floating labels.

Please provide support (e.g. base classes) to help structuring and modularizing applications. Otherwise the framework is another control library and will not compete with full JS/HTML5 like frameworks like Sproutcore, ExtJS4. Most of the UI frameworks lacks of such support, especial for building serious enterprise applications.

Add a new Kendo UI component to display a record vertically (Or add an option to the existing grid to change the orientation of the records).

Usually, I was using vertical grid to display a single record but some people might need it to display more than one record (ex: when you compare items on best-buy web site)

The vertical grid could also be used as a property grid (http://www.telerik.com/products/silverlight/controls/propertygrid.aspx).

Add the AJAX FileExplorer to the MVC Controls Toolset with additonal built-in features I would like to see:
1. Support for UNC paths so that the root folder may be located in a network share as opposed to a folder under the application folder.
2. Support for sub-pathing so that it can be dynamically programmed to support direct display of target folder without having to navigate to the target folder
3. Built-in Delete function to complement the built-in Upload function
4. Optionally select display of a checkbox column to allow for multiple selection for items to be Deleted or Downloaded
5. Built-in Progress Bar for Upload and Download functions
6. Optionally select automatic filtering of hidden files and directories from the display

SNS and e-business always use this for make a comment.

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.