In a nutshell, yes it has. Overall it's due to the adjusting and reduction of schedules by the airlines and the new runway. (it's still used for arrivals only)
Both UA and AA have reached the point where the Regionals are actually flying more than mainlines are, so spacing for both arrivals and departures aren't as great.
What you also see is a shift to canceling more than delaying a flight in the event of bad weather.