It would go great batch syncing. And controls would redraw(refresh) just once when array of items is added. Not refreshing control and manipulating DOM(very slow) each time the item is added to datasource.
Example use case: scheduler month events copying...

It would be nice to be able to specify in a datasource filter two fields and an operator for the sake of data reporting. For example, where "completed date" is greater than "promised date" or "Actual cost" is greater than "estimated cost."

This sort of thing can be accomplished by calculated fields; a filter of where "cost overage" is greater than 0. The down side of the calculated field approach is all comparisons need to be pre-defined. 

Ignore language specific characters when filtering. Example: search phrase "Deja" should find word "Déjà".

We use the new version of SignalR which is 2.2.3 currently and it seems the Kendo DataSource cannot bind to it. It would be awesome if Kendo supported it. 
Here is a link: https://www.nuget.org/packages/Microsoft.AspNet.SignalR.Core/

I would like to be able to dynamically update the text in my button by binding to a viewmodel.

Thanks

We need an option to make the datasource immediately drop the current in-flight data fetch request if another one comes in.

Currently, if the user clicks around several times in a row changing grid datasource parameters too quickly, several requests get fired off, but the grid waits for the very first request to complete before issuing the next one. This makes the user's wait time twice as long and also makes the grid content appear to switch back and forth as requests complete one after another. Very unpleasant effect.

Right aligned columns are common for number fields and it would be nice to simply set a property in HTML and/or the view-model:
E.g { "field": "amount", "align": "right", "title": "Amount", "width": "110" }

This feature was already requested in another post, but it was missunderstood. (http://kendoui-feedback.telerik.com/forums/127393-kendo-ui-feedback/suggestions/11578722-support-sorting-datasource-groups)

The idea is to allow for Groups in DataSources to be sorted in ways other than alphabetically; this will allow for certain groups to be given priority.

Please consider adding support for the new improved Signalr core to be used as an async data source and or server side rpc which would allow for greater mvvm spa applications 

"WebAPI now uses the DateTimeOffset time as a main type when it comes to dates. However DateTimeOffet requires the Model(that the dataSource creates) to keep information for both Date and Offset which is not possible with the current architecture of the DataSource and Model of Kendo." Based on http://docs.telerik.com/kendo-ui/aspnet-mvc/helpers/grid/how-to/oData-v4-web-api-controller
Please add full support, also when working with Dates. Thanks.

Add sort/filter events or add an extra parameter in the 'change' event object so that we can detect if a data source was filtered or it was sorted.(Mostly needed when working with grids)

Wish to have a "reset" or "clear" method to restore a DataSource object to it's initial unpopulated state--specifically when used behind a search text box, and need to clear the datasource when the user removes all search text.

The DataSource API currently includes the methods pushCreate, pushDestroy, and pushUpdate.  These methods roughly correspond to add, remove, and set.  Unfortunately there is no pushInsert to enable adding new items to the data source at a specific position.  Adding such a method would be consistent with the existing add/remove/insert methods.

Possibility to add filters to hierarchical datasource, that execute recursively.
Use case: In TreeView we need to search for some element text, we need to see elements that contain some text and their parents expanded. Filtering could be usefull here.

dataSource: {
       type: "odata",
       typeversion: "3"
}

this.dataSource.sync().done(function(){//fire after...}).fail(function(){//any time on fail...});

One should be able to group by a specified field, and then sort the groups themselves NOT by that field but by another field. For instance, it is currently not possible to sort data by its name but order it by its date.

In order to clearly identify if a datasource operation is successful, 
two alternatives are possible:

1. Add success event to the datasource in order to get datasource operations separated from update, destroy, add. 

2. Enhance change event by error array. 
Currently, the change even is fired even in case of an error. So, at least an error array containing error messages should be available, together with a property "hasErrors".

Though KendoUI already has an MVVM style binding, it would be much better to have a css binding allowing us to set class on HTML elements based on arbitrary conditions.

Just look at the Knockoutjs css binding.

Add a visible property to the column items for the grid control. Then provide the value in the view-model. This would allow us to declare the columns in html and manage their visibility in the business logic.