Look at LHR on Google Earth and you'll see why. Although it still shows a lot of "construction" work, you can only fit so many stands there so when you think of how many BA flights leave from LHR you can do the maths as far as flights and stands goes.
Being bussed to a plane at Heathrow isn't really unusual, we used to enjoy watching some of the cuties walking down stairs to be bussed to the terminal after they had returned from somewhere a bit warmer, kinda made avoiding the baggage tugs a bit more enjoyable, and they were not exactly on some of the more remote stands.
Oh, find me an international airport anywhere that doesn't direct you to the *cough* cheap shopping. I even remember MSY (if anyone is heading to New Orleans in the near future, can you look for the two days I lost?) advertising their cigarettes were cheap "compared to London Heathrow". They're all at it, even Minsk 2 made sure the first thing you saw was somewhere to get perfume/hooch/smokes. Decent vodka though, that was a plus.