Two FYI's...
1) anybody who is flying ex-NWA flights and who had bulkhead seats in your reservation, check your new Delta records. It's pretty much guaranteed you won't have bulkhead seats anymore.
2) When I called to restore my seats for an upcoming February trip, Chisholm didn't have a good rationale as to why Bulkhead seats aren't selectable anymore. My own personal guess is that they're holding them back for FAM's, handicapped/assisted or much more likely, future Roach Choice sales. The Elite line agent said that if enough frequent flyers write in to complain about this, management may change their mind regarding bulkhead seat availability.