Rather than generalising about whether trolleys should be used or not I think it would be more valuable to look at which particular aspect of trolley use has caused accidents, and then address specific high risk areas.
I do recall that the Australian B47 accident was considered to be caused by the skid hitting a lip to the trolley after drifting, and it has been rumoured the Germany MD900 was caused by a similar problem, both triggering dynamic roll over. Answer - never have raised lips/obstructions on trolleys.
Other obvious risk areas for example are trolley size, height differential to the ground (which should be as minimal as possible), lack of anti skid surface, and poor braking security.