The top heavy MH tends to roll with the variations of our current highways (and what is said above about aerodynamics of a MH).
Trackbars tie the frame to the axles to reduce the reaction to the body roll.
Anti-sway bars try to reduce body roll during cornering and also assist with the uneven road surfaces to reduce body roll.
Air bags in most cases provide a cushioned ride and also assist in keeping the coach level if one side becomes loaded more than the other.
Steering controls such as Saf-T-Plus, etc. are designed to keep the steering centered and prevent sever steering reactions to blowouts, potholes, etc.
My motorhome came with 3 of the 4 and I added the 4th for $550.