I have a prototype using Ext.Direct, so after using it I understand better what it does for me.
In some cases, it complain on the client side that I didn't provide the right number of arguments, and it batching my AJAX requests when many are done at the same time, like in the initialization of my UI.
Using JSON directly without Ext.Direct is quite easy in both Java Spring, and .NET MVC.
The value of validation of the number of arguments is low. My server would tell me anyway. So it seems the only value is the batching of requests.
With some customization of Ext JS we should be able to get batch JSON, instead of using a proprietary mechanism: http://groups.google.com/group/json-...b/json-rpc-2-0