If for some reason the TV stations DO decide to go to the new One WTC tower, I'd recommend keeping the Empire State Building facility intact.
A transmitter engineering executive from one of the BIG NYC TV stations, has told me that moving the transmitters again just makes no economic sense. So few viewers now actually take the over-the-air signal, that it is hardly worth thinking about.
The TV stations all have fairly new plants installed on the ESB because of both the switch to digital and building new after 9-11, and they have no real reason to want to move again.
As I said in a radio thread, the one wild card is the planned new skyscraper to be built near the ESB which "could" cause problems, but there were signal problems from the old WTC site too. And that new building has been put on hold by the recession, and it may be years before they even break ground.
OTA is a zombie. It will not see the light of day once that tower at Penn Plaza is built to a height that would have mattered in the good ol' analogue days.
The building height will still be lower than where the mast starts, anyway.
Multipath in analogue, shows up as a blank screen in digital. In analogue, multipath still had a picture. In the digital world, we threw the baby out with the bath water.
Jeff in Sa-ra-so-ta!