The other major factor is construction.  A unibody construction will always have a lower tow rating than a body on frame (where the hitch can be mounted to the frame).    Most modern SUV's are unibody and more luxury pickup trucks will be (Honda Ridgeline, the new Mercedes truck).    Tow ratings will be limited (maybe a class III hitch max).     The good news is - that is more than enough for most people's needs.   It's when you have to haul around heavier equipment and need a class IV or 5th wheel that you really need a pickup for towing.

Another thing is transmission and brakes.   If you have a really light vehicle, with small wheels and brakes - you might want to have  trailer  brakes even if the load is fairly light.  Also if you tow regularly - a transmission cooler is a good idea.

Last - front wheel drive warning:   I have personally witnessed a front wheel drive van slide backwards down a slippery boat ramp as it's front wheels did a burnout.   Boat launches and FWD are dicey.