LGS6753
I would just dispute one of your points - in my view. LGW is a more attractive option than LHR due to the number of incoming LoCo flights.
The most attractive airport for those living in London may well be LHR, but for those of us not living within the M25 and needing a connecting flight to our final departure airport, LGW, AMS or FRA may be more suitable, given the number of incoming flights fromother European destinations.