I disagree with the engine power argument. The Pathfinder has plenty of horses (and torque) under the hood for reasonable performance at the recommended 60 mph (100 kph) maximum towing speed. I'd worry more about exceeding the axle/tire capacities and disagree about exceeding the hitch rating. (Check to see what the hitch rating with WD is. Usually it's higher.)
I've climbed 1 mile 9.5% grades while towing my trailer at 45 mph, and 6.5% long grades at 60-50mph (starting at 60, letting it drop to 50 during the climb), I don't exactly have an overpowered vehicle, and end up passing semis and much larger trailers/TVs and RVs. One does have to be properly equipped for heat handling, know their engine, it's power bands, and how to make proper use of them. (One should also know how to go downhill without over-using the brakes.)