I wouldn't be worried towing around a moderate sized popup with a new Pacifica.
I would take some precautions like you're saying with trans cooler if it doesn't have an adequate one.
The big question is duty cycle. Few weekend trips to the state park, low miles, low altitude, not in the mountians, I wouldn't hesitate.
Major family trips, loaded for bear, X country, dead of summer bucking a head wind across SD before climbing the bighorns , Snowies and hitting Colorado for some back country? I would want a more capable tow rig without a doubt.
In between those scenarios? Judgement call and take it easy on the car if you're trying to make it last many years.
