I wouldn't get too upset about it. I also would not waste the money to change gears. With the 6 spd, it's not a big deal. Trans cooler, maybe. Actually, if you have a digital trans temp readout, just watch it and pull over if it starts to climb over 225F.
The ratings are created by testing in extreme conditions (at least as far as gearing). If you are not towing in mountains, 115F heat, or tearing across the country at 75mph, you're not going to magically melt down.
We have already established from the "what's your real weights" thread that 50+% are overweight. Some are waaaay over. If you don't go drastically over the limits of even the 3.42 gear Yukon, you'll still probably be in the first 25%ile of those that are overweight.
Just don't go overboard and keep doing your homework to find something light but I don't think you are doomed to a pop-up.