HH
You are right , we do not need to be the biggest just for the sake of it, but we need to be comparable or competitive -real estate alone means CDG is and always will be bigger than LHR. However we have to allow for reasonable expansion-preservation and growth of the BA hub, rather than just giving the game to Emirates, and avoiding the long holding and ground manouvering delays endemic at present.
LHR has already started a slide downwards and unless it is arrested it will end up as a sort of Gatwick or Orly on Euro standards. Economically that's not good for UK inc and certainly not good for London and the South east. If I was promoting the idea of a really big airport -biggest in Europe- then I would be a Boris fan
PB