Some computer operated planes are made to be passenger friendly and when they turn they turn very slowly.
In NAV/LNAV/RNAV and approaching a flyby waypoint, the FMS will increase or decrease the radius of turn for the speed so the aircraft shouldn't overshoot the FMS route/radial regardless of the speed.
For "established, I'd use the same definition for an approach: </= 5° and staying within that (not whizzing through the radial, pulling like a b@stard trying to stay on it!
).
As for "turning slowly"...