I flew one of the newly configured 757's from JFK to SLC. Sat up front and actually enjoyed the seat as much (if not a little more) as the 767 BE seats. The added lumbar features on the 757 seat were good once I finally figured out how to use them.
This was a 5 hour flight, so the extra comfort on the domestic haul was nice.
That said, I didn't pay for BE service so perhaps this wouldn't be meeting the needs of each and every paying customer.
It isn't like they are only putting a domestic first class seat in there and masking it as BE.