Just published my Ajax library. It is very much like jQuery. In fact it is a micro library I built so I would not need to load up jQuery. It comes bundled with FN_Deferred. I admit it is not as full featured as FN_Deferred, but it is very much like jQuery Ajax, and could be the replacement you are looking for.

Go micro, Go Fast.

https://github.com/josephtveter/FN_Ajax

I just published my micro Promise A Library. If you are looking for a micro library for your Deferred Objects look no further. This library was built to support Promise A, can easily replace jquery deferred if you are wanting to lighten the load on your site, and unlike window.Promise it can handle multiple arguments to callbacks. All that and it weighs in about 3kb. Give it a try. https://github.com/josephtveter/fn_deferred