i didnt say netcode - the underlaying tickrate of the game, which ties the game to time. wc3 replays are just few kb big, that means they only contain coordinates - its a mere text file. to translate this into gameplay, the game needs to know what happens when - this also includes animations being at point x in time y - otherwise the state of the animation would be quite random in a replay.
that means everything, including animation frames, get synced to the game time in, say 30hz intervals, and i suspect this is the reason unit movement and unit animations look so stuttery - i guess the internal tick rate of wc3 commands it. in wc3 both players see the same thing, theres no modern lag compensation in place.
now if you increase the internal tickrate of wc3, units and animations should play smoother. that also means replays should become bigger and network traffic should increase.
this change should “fix” classic and reforged alike. the animations themselves are smooth enough to support that.