Currently it is only possible to map data from prompts inside the Request Offering to the workitem.
I'd find it very comfortable if it was possible to map e.g. the Created By Users' DisplayName,UPN, etc. as well. Often we have script or runbooks which only write this data into the description of an RA or MA. If we could map data from the created by user directly, some of these Scripts would become obselete and we could reduce the amount of activities in these templates.