A lot of people like a tow vehicle. It depends on what you like. If you had the TC on, you probably would still get stuck with the current tires. I'd consider a tire upgrade if you don't already have solid tires.
If you like the current truck, you probably won't like a Ram 5500. You'll pay a lot more in fuel costs, and the ride will be noticeably rougher. The 5500 has 19.5s which have a lot stiffer sidewalls which will translate to rougher ride.
I realize you will be over the GVWR, but your rear axle and tires should have a lot of room for more weight. Flat towing the Rav4 with tow vehicle brakes shouldn't hurt either braking or payload. In fact, you could transfer a few just in case items to the Rav4.