I think the facebook plugin needs a little bit more documentation in relation to the facebook app review process.
For instance the sample shows a hard coded text with the share link, but this will fail their review - you must ask the user for the text. I don't mind the sample doing it (it's just a sample), but a comment to be aware of review criteria at that point would prevent some heartbreak later.
Another example is permissions - the documentation doesn't indicate which method requires which permission, which makes life a bit trickier when trying to figure out the minimum set required.
Then differentiating async and sync methods - login is sync but share link is async? It's not clear, so can be tricky to get the work flow right without resorting to trial and error.
Finally the minimum android sdk supported is 15, but I wanted my app to support 9+. So I implemented a jni call to get the android build version and only call facebook APIs if sufficient. The jni call was pretty easy to implement, but it's something that the plugins could provide (like a method that says whether a capability exists at runtime).