Currently we are able to set a label expression with ArcPy by using the lblclass.expression method. However, there is no way to check the "Advanced" box from ArcPy.
There also doesn't appear to be a way to select with language parser is uesd (VBScript or JScript)
It would be very helpful to have this capability. In addition to this, being able to load precreated label expressions from ".lxp" files through ArcPy would be great.
I would be extremely helpful if all of the settings in the label manager were exposed in ArcPy which include Label position, Fitting Strategy, and Conflict Resolution parameters. All of this would fully enable complete automation over setting up labels for features.
Finally, it would be nice if the label engine (default or Maplex) could be set within a python script.