A lot of airports that have diverse vector areas in their departure procedures will have standard headings they assign in takeoff clearances depending on the traffic flow and the filed departure procedure. KSLC is one example: they nearly always assign the same initial departure headings for any given SID and traffic flow, then the departure controller will either give more vectors or, more often, clear them direct to the first or second waypoint in their assigned SID. This would also help in places like PHNL, where certain headings are always assigned to avoid overflying the city and ensuee terrain clearance. It seems like it would be pretty simple to incorporate into the existing individual airport SOPs—the logic would just be “if runway=[x] and SID=[y] then assign heading [z] else [revert to default logic].”