RAT, according to the reports, the Asiana pilot was having to exert ~80 lbs. force on the yoke as the airspeed decayed towards stall. I think we can safely assume he wasn't doing that with one hand on the throttles
.
Although not a pilot, I've spent lots of time on the flight deck during flight tests - and observed countless simulator sessions - and the PF has always had one hand on the throttles during approach/landing. I've assumed that was SOP and pilots who flew Boeings were taught to do that.
BTW, I don't think BA 38 (777 that landed short at Heathrow) is particularly relevant to this discussion. Those engines were incapable of producing additional thrust due to the ice-blocked heat exchangers, regardless of how the thrust was being controlled. There was nothing that the pilots could have done to prevent the crash landing.