FCA developed a fix for the Wrangler that involved a larger steering damper.
Are you certain the battery must be disconnected prior to towing a Grand Cherokee? Non-Jeeps have had a similar problem caused by the car battery draining while being towed and the electric power steering system losing power. Their fix was to run a battery charge line from the motorhome to the car.
I'm actually wrestling with the same question you asked. If we do decide to go with a GC instead of a Wrangler I may have the hitch upgraded to a 7,500 lb unit just for more safety margin. I'll still have the 5,000 lb limit for actual towing.
I'll also ask the company doing the work to provide attach points for the safety chains and breakaway cable that are anchored to the frame independently of the hitch.
I saw a few pictures of motorhomes where the hitch tore almost completely loose. Had it broken off totally at highway speeds with the breakaway cable still attached <shudder>.
Even just moving the breakaway cable attach point to the frame instead of the hitch would help. Some people have added a steel cable loop around the frame to relocate just the breakaway cable attach point. That would be better than doing nothing.