Differing approach, no pun intended.
The closest thing off the top of my head to LHR is PHX, until recently it had two runways, a baotload of GA of differing categories and is a hub for two major airlines. It was a breeze to go in and out of. Little hassle from the controllers. Of course the WX is usually better. As busy as it is, its nothing as compared to the hyper busy airports that are at the end of every other leg (hub and spoke). The fixes you seem to hint at are waaay above our paygrade. We control and fly, not allocate money for new airports, new equipment, massive changes to airline schedules.
Bear in mind places like ORD and ATL are pushing a million takeoffs and landings a year. Would I love to see ORD as a couple of parallel runways, sure but it isn't going to happen. Winds shift frequently and the need for crossing runways exists.
GA exists in a huge way here and is essential. People have to meet connecting flights within the bank, etc.
As a very average line pilot with average skills who flies into the busiest of the busiest airports, I enjoy the challenge.
Your argument comes down to holding up LHR as the model airport for comparison to all others, no matter others being a helluva lot busier and complex. When I do compare airports that are roughly as busy, I find them pleasant and easy to operate at.