I know there is the tried and true <for L in layers:if L.name=="oldname":L.name="newname", but is there a way to rename subtypes? I am working on a project where I am appending translations onto the subtype names, but I only want to change it in the TOC and not in the data itself. I know this can be done manually by selecting the subtype in the TOC and typing, but can it be done systematically with arcpy?
I don't think it is possible with arcpy. When you make changes to the TOC without changing the data, the change is saved only in the mxd file. I'm not sure you could or would want to edit the mxd directly.