It would be nice to have Promises and Deferreds added to Ext JS.

Promisses are used extensively in jQuery and Dojo. Also, DeftJS uses them as well.

See the sample chapter from the Async JavaScript book which explains why Promises and Deferreds are helpful.

https://leanpub.com/asyncjs

http://samples.leanpub.com/asyncjs-sample.pdf

http://deftjs.org/