What are you trying to do? You could read almost nothing from the database of your model in a GDL script.
I'm not totally updated in ArchiCad 11 though, I think there are some improvements in right direction but not much that would help us.
I don't think GDL can be developed that far because of how ArchiCad work (accessing GDL at every update for example). I think we need a new scriptlanguage (with a RUN button) that are in the middle of GDL and API. GDL are objects, not a scripttool to give us information and do something good with it, even if Graphisoft have give us some possibles like componentscripts.