"keep things as simple as possible"
simple where? you're servlet now has a facade to allow you to pretend that it is a RESTfull interface. It isn't a RESTfull interface, it is REST + some pollution.
sarissa (which I mentioned in my first note) is cross browser support for XmlHttpRequest so you don't need browser detection. Ok, you'd still be excluding lynx|links but were you including those anyway?
Complicating the client side a little is preferred in REST, the view being that life is complicated enough on the server already.
And you're article is titled "the REST of the web".