I used to support Boris Island but went off it when I realised how it clashed with Schiphol and the SS Richard Montgomery.

Personally I think that:

a) Gatwick get another runway and expand as a point to point airport.
B) Heathrow and Stansted swap role. Heathrow becomes a regional airport effectively using the facilities it already has close to the centre of London. Stansted gets several more runways and a high speed railway link into London so it can take over as the main international hub.

That way the South East gets an expansion in capacity and we get a hub airport outside London (and a similar distance out as Paris CdG) with the space to expand. No airport is closed which is the usual complaint about Boris Island taking over from Heathrow. Actually the South East might be better served as currently if you want to get a cheap regional flight you have to go through London to get to Luton or Stansted.