As others have said the so called slip skid indicator is very sensitive and shouldn’t be used like on a light aircraft.
Boeing refers to the Slip/Skid as body lateral acceleration.
I’ve always surmised that it’s slip/skid indication in a turn is the fact the IRUs are some distance forward of the aerodynamic centre of the aircraft.
The 747 in particular is very good inherently for turn coordination and does not need “help”, handling the big jets has a good read.
One thing that isn’t really talked about is the large amount of roll induced by the rudder which can cause instability.
3 large rudder inputs:
1. final
2. Flare
3. During the go around!