Mattress pads on all flights is a big improvement as well. Recently flew another airline (AA) on LAX-LHR with no mattress pad, and the break in the seat cushion was very noticeable on the overnight flight. Flew VS back and appreciated their mattress pad when I took a nap on the daytime flight.
Flights over 12 hrs. To me it seems cheap to exclude them for flights less than that duration. Flights between 8-10 hrs could surely benefit from that amenity. And there are far more flights of this duration than there are exceeding 12 hrs.