It'd probably help if we discussed this in a bit more specific terms since I'm not sure if you're referring to the GStreamer elements or what regarding the "outsourcing" of profiles.
Anyway, for the GStreamer elements, there was always a dependency on the GStreamer library to compile these while they were within BlueZ. With BlueZ 5 the dependency is no longer there. That said, this particular example isn't really that valuable since the GStreamer elements were never used for much else than testing. A typical distro would use something else like PulseAudio for properly working A2DP and from that perspective there really isn't much change going from BlueZ 4 to 5.