You are close to the mark there clark y. Morning departures often only use 21 (nil or little wind) when 24 could be used. The reason given is noise abatement. It would be reasonably easy to create a departure off 24 which required a right turn to clear most noise sensitive areas. Having a second runway for departures would make a huge difference to flow rates.
As for LAHSO, I never see it in use over there when I arrive or depart. Seems to have been a waste of time and effort installing the lights.