Increased % long haul flights, new runway
The increasing proportion of longhaul/widebody flights is entirely consistent with the ambition of (particularly) BA to serve more and more N American destinations at the expense of the rest of the world and especially UK feeder flights.
If Heathrow is to continue to function as a hub for the whole UK, and thus a national asset, what it needs is not a new runway, but half a new runway, ie one suitable for short and medium haul flights.
But privatisation, of BA and Heathrow, probably put an end to any such strategic considerations...