The 737, at least in classic guise, was traditionally very stable in Yaw. Unusually so because the swept wing jets usually require additional yaw damping becaus

The 737, at least in classic guise, was traditionally very stable in Yaw. Unusually so because the swept wing jets usually require additional yaw damping because the geometry naturally means on yawing one wing gets longer and the other gets shorter as seen from the point of view of the airflow. So much so that the Yaw damper on the 737 was not on the minimum equipment list for dispatch. On other aircraft like the 757 having one of the two yaw dampers out of service limited dispatch to return to a maintenance base (from memory so it might not be exactly that). I'll keep my eye out for the report on this one because I'm not convinced the initial reporting tells the whole story. It's not unheard of for pilots to damage otherwise perfectly serviceable aircraft through in-proper rudder application - American Airlines Flight 587 being a horrible example.