Our 1st 5th wheel rv trailer was a new 1984 29' Aljo (no shocks) 4400 lb tandem axles rear bath pulled with a 2500 chevy 5.7 engine 4L-60 tranny.
This trailer pulled easy with no bucking. A empty flat bed GN/pintle/bumper ball trailer can kick occupants in the cab even with my one ton drw trucks.
However every trip all the contents cabinets/drawers in the rear bath were scattered every where.
In 1990 I added shocks (Kit from Monroe) on each axle.
Ride in the cab had no change but no more contents scattered in the rear bath.
Our last two 5th wheel rear kitchen rv trailer came with shocks. No issues with ride or shook up contents in the rear kitchen.
Small Light weight trailers (rv or non rv) with lighter axle capacities probably don't need shocks.