These changes do not break any existing functionality, Field Expansion is an addition to the API. Field Expansion is basically support for very simple joins.
Batch Request support has existed for some time and allowed similar result sets to be retrieved. Batch Requests are significantly more complex to construct and are not well supported by tools like Facebook's Developer Open Graph Explorer.
It's fairly standard practice to provide a list of backwards incompatible changes (along with instructions on how to mend your code) when making changes to an API or a framework.
Maybe these updates to the FB Graph API don't break anything? Would be good to hear from someone at FB about this.
Fantastic news, nested batched queries on the graph API were a total crapshoot in some circumstances last time I tried (FQL works much better). I may have to update some code now...
Is there an advantage to using the graph API over using FQL? It seemed to me like FQL was more flexible in that you could specify more complex and general queries using a unified interface; am I missing something? (I easily could be missing something: I find that the API changes so often it is difficult to keep up with.)
Mostly simplicity. "graph.facebook.com/id/photos" is easier than multiple round trips or nested queries, and in general it's easier to grasp for people who aren't familiar with SQL (not me, but lots and lots of people never have to touch the stuff).
Personally though, I find myself waffling between the two depending on which gives me the information I want, the most easily. Often that's the graph API, though speed can suffer immensely unless you only request the fields you need (e.g. counts add a lot of time to a request).
