I’ve noticed at LAX for example, there is no rhyme or reason as to how dual runways are used.
IMO and…experience as a more than frequent flyer, the inside runways (closest to terminals) should be used for arrivals. They don’t get hung up with crossing runways at a very busy airport and…on time arrivals. That is a big deal for every airline.
Outside runways are used for departure. They can make up time in air and… their on time departure starts when they leave the gate. Not once wheels are up. If that were the case US airways would have always got slammed for departure stats. Ever get on a 5pm flight out of Philly? You could be in line for 45-60 minutes between the gate and number one.
That and another pet peeve… it’s not “line up and wait”… it’s “position and hold”. Just saying :-)