Surely the main problem LHR faces is that it's had to evolve into a modern airport, with bits and pieces being added on over the years - rather than being a grand design built from scratch (like many of the airports it's often compared to). However well it's managed, whatever incentives / fines are in place, and whoever owns it (and there certainly are issues here), it'll never be as efficient as SIN, HKG or AMS.

I'm pretty sure that if Heathrow were to be built again tomorrow, it would be a world-class airport (well, at least one where the travellators work and the queues for security aren't quite so crippling), and will be interested to see what T5's like when I first use it.