Good for exercise is the only complement, I guess.
I have a flight into T4 in a few weeks. I am going to time myself how long it would take to exit terminal once; in flights from recent weeks, I would say it's taken me 10-15 minutes. Even at other terminals of JFK, and most other US airports, including international arrivals, I have only needed around 5 minutes to exit - yes I am a fast walker, and I don't check luggage.