Descriptions of handling problems vary a lot, so be cautious of simplistic answers. If it is really body sway, you need stiffer anti-roll bars. Sometimes the coach body builder puts too much body on the chassis, e.g. too much weight up high, off-balance, or just plain excessive weight for the GVWR.
What some people all :sway" is a steering issue, better known as "wander", i.e. the coach seems to angle in one direction, then another as the driver over-corrects. This leads to the feeling of a "swaying motion". That can be either a driver skill issue or a need for a panhard rod (Tru_Trak or a SuperSteer Track Bar).
I have written an article on Motorhome Handling Problems in the FILES section of this site - see iRV2 Forums - Files - Motorhome Handling Problems & Solutions
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL