I don't think my heart could take it if that happened. Much of the majesty of taking Amtrak is being able to show up to the station in the downtown core minutes before departure and simply hop on the train, and then hop back off in the downtown core of your destination. I would take arriving at Moynihan Train Hall over JFK ten times out of ten. If they made it an undignified time-consuming hassle I might think to myself, "eff it, megabus is so much cheaper."