Brakes, engine/oil cooling, final drive gear. In all reality it will tow just fine. even the 2.4 can tow the 4500lbs. It more going to come down to the legality. If there was to be an accident and you are found to be towing more then the factory tow rating then be hefty fines and liability issues.
Legality has nothing really to do with it, with the vehicle per say.
Its warranty coverage. I guess if you slap on a hitch and the trailer pulls it off the vehicle or the hitch fails then yes you will have some personal liability.
As far as state laws (legality) go they vary on trailers. The big issue is trailer brakes at 2,000lbs in my state and trailer lights size by trailer weight etc.
The big issue is the manufacturer wants to protect itself and the warranty of the vehicle. Having a full size spare in not included in stock Cherokees unless optioned like in the tow pkg. Get a flat and using a temp type tire is not a good idea if you are towing. Its a huge safety issue that will lead to a serious accident.
Also, if you tow with a non OEM hitch and trailer wiring connection there is no way the manufacture can warranty the tow not knowing the hitch and how it was attached. Also you absolutely can not wire power into the wiring as it exists. It must be integrated separately. You can damage the vehicle.
If a dealer puts a Mopar hitch and specific wiring into the Cherokee then you will be in a much better position to tow if you have the proper cooling attachments.
So many variables, so that is why you see the limits the manufacturers put on towing.