As far as I know… to me seems the mayor problems in blender with the FBX is related with the import into blender for this reason:
(the bones in blender have names in 3 parts of the bone , other software only 1 name for all bone (on the join)
://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.73/Addons
And well they change the Api for the FBX exporter ( i not see for now ) but I suspect the changes are only the names of the parameters passed to the export function (like what happen for the version 2.72)