The more my sims interact with Greg/Mr. Greig, the more I feel that he'd fit right in with them. What probably says a lot about my playstyle and/or sims than about Greg. Like the one instance where Greg gave the most underapprecciated of my cops a hug, only to attack him with his very next action.
In any case, after I wrote "meh, just an npc", I think Mr. Greig now has won his place in my cast. I'm pondering to make him marshall or sheriff (I always forget which is the one for towns and which for the whole region) and put a badge on him in CAS. The locals (probably): "Greg is a DPD officer? Ah, that of course explains his behaviour."