We've had this discussion before, about that place.....I really feel that the whole Chem Plant and the area around it was vastly underused in this game. Outside of the few missions that take you into the area, there is nothing going on there. Add to the fact that characters don't spawn over there in free roam only adds to the underuse of the area.
As to the 'circle', I can only assume it must have had a purpose planned at one time, but got dropped along the way as the game was being done. IMO, it would have made an excellent place for a 'fight circle', aka, the Townie's version of 'The Hole', and that whole back lot would have made an excellent place for the Townies just to hang around, just like the Bullies do at the Parking Lot at school.
