The task now, is to make it work properly, instead of it becoming another ill-planned, on-the-cheap, in-the-wrong-place construction (like the M25, the Dartford tunnel, Birmingham airport, Bristol airport, or Luton airport).
Your understanding of history is wanting I am afraid.
There was no great design years ago that has led to this structure.
These airports weren't suddenly built to the size and capacity they are at now, they grew over many many years from being old wartime or aircraft manufacturing airfields.
If you could start all over again that would be great and your end result would't look like it does now, but you can't.