My limited (once only) experience is that in fully flat mode the seat is not as comfortable as CW as a bed, it juts out in the wrong places slightly. Also window seats in CW have better privacy, particularly upper deck. Otherwise I can certainly see your point of view. And I certainly agree that JFK T8, along with SFO T2, are the best big airports in the USA. However there are 3 things that stop me from booking this service:
1) The lack of consistency on the hard product, especially if there is an equipment change, the alternative is quite dire. With BA that is hardly ever an issue.
2) AA's staff / soft product is not as good as BA at its best (yes, there is consistency issue there I admit).
3) CWLCY.