Yes, through airports have weird ATC procedures, they also move about twice the tin per day as Heathrow. While you British weedle out slots to LHR by the thimble, all are welcome here. Even if you don't like the place.
Simple reason for being able to move twice the amount of tin, the busiest airports in the States have twice the amount (or more) of runways.
Doesn't matter how flash (or not) the ATC is, one runway can only accept a finite amount of traffic on it. Give LHR the same number of runways as the ORDs and the DFWs and I'm sure we (the ATC) could shuffle just as many aeroplanes around... it's not rocket science after all.