Right now other JS UI libraries allow the autocomplete dropdownlist to dynamically size based on the returned content. KendoUI sets the width to the width of the input box. I understand this looks nice but doesn't work for all business aspects. An example is my company needs to enter search criteria but the return results is the code and description. Since this can get longer than the input box the text is wrapped. This confuses users as they don't know where one item starts or ends. We use to modify the source files to fix this but the Q2 release changed a few things and stopped us from doing this.

The grid and autocomplete widgets really need no-data templates which display when the returned data is empty. The MVC controls were pretty good at this.

When bound to oData, the autocomplete contains filter should treat each WORD as a new "substringof"....or make a new odata advanced contains type\property.

This is more what users expect when searching...and the odata spec has it covered.

http://www.kendoui.com/forums/ui/autocomplete/odata-google-like-filter.aspx

Fast and responsive UI rather then flaunt and animated. 

I have played for a while with the demo of the components.
What I noticed is that components with popup elements, such as ComboBox, DatePicker, TimePicker, ... have a small but visible delay, which becomes quite annoying with time.

Look at ComboBox demo, it seems there is some delay due to pre-configured animation effects on the control.  In slower browsers (take Firefox 6.0.2) the delay is obvious. 
The support for animation in general is a cool idea, but in most business applications it is not welcome by users who use application on a daily basis. 

Personaly, looking at the demo I am not sure if I can rely on kendoUI if my application designed for "do the job" rather then "enjoy UI".

I think it would be very nice if the demo has settings to disable all animations, to run it at full speed and demonstrate rich AND really responsive UI.

I'd like to be able to style the matching text from autocomplete, so I'd like the option for kendo to perhaps wrap the text in a span or something I can get a handle on...

So if I typed "Back" it'll give me results like this
<li><span class='t-match'>Back</span> to the future</li>