Boeing certificated the -400 with better rudder response than the Classic. Can you imagine a company like Boeing pumping up the engines and systems of the 747 and not bothering with making any improvements to asymmetric handling? In all respects, the -400 handling was vastly improved. Two engine out approaches went from being a crisis to a relative breeze on the -400. On the Classic, you were committed to hitting the ground, on the -400 the whole thing was far more civilised.
I'm qualified in both, current in the Classic, and last flew the -400 in June.
The rudder "response" is virtually identical in both. The rudder authority, relative to engine thrust, is virtually identical. That is, both are just short of the limit at a V1 cut -- both can overcome a bit of yaw and drift rate, but not much. Vmcg at max thrust, 15C, sea level is 133 in the -400, 129 in the Classic -- not much difference, but with the Classic still having a bit more margin.
Manual handling of the Classic is, IMO, better overall than the -400. The exception is throttle response, which is much better in the -400. However, the -400 does have significantly more ground effect apparent, which will aid a 2-engine-out situation IF you can get in the air under control.