My penn'orth: it's a good option in a segregated area (upper deck of 747 etc) for those who do want to sleep and not be bothered late and early by the dinner/breakfast crashing and banging (Amen to those who cite the DEN route, even in F you can't get a wink of sleep for hours).
But, it should be just that, an option. And only implemented on routes where the timing makes sense. And only in one area (so it's already sounding like a seat-allocation nightmare!)
My experience of JFK pre-dining is confined to walking in the room once, smelling a mix of stewed vegetables and gas-burners like the worst buffet you ever went to and walking right out. Plus not everyone has the time to eat on the ground and some of us are still not so jaded that we enjoy eating in the air.
Clearly a cost-cutting exercise; nothing wrong with that (any of you guys BA shareholders?) as long as it can be configured with providing an additional option and nor p***ing-off core customers. I hope to try it out sometime;no doubt others will first and we'll come back to it.