This Quote from the GM article is a bit concerning:
"We’re shooting for towing confidence,” he said. For highway passing, the new engine reduces acceleration time from 50 mph to 70 mph by 1.5 seconds when towing a 10,000-pound trailer. Without a trailer, it can reach 0 to 60 mph in 7.1 seconds."
I do not know about everyone else but stopping capacity provides me with confidence while towing.
In regards to heavy loads you always hear "you may be able to pull it but you can't stop it". While I agree stopping ability is of utmost importance it really is the job of the trailer brakes to stop the load on the trailer. I towed a load grossing 42,000 lbs (truck, trailer and load) the other day with with my 16 GMC dually. It was overloaded but surprisingly legal. I only hauled it from my house about twenty miles to the scales and then back home. I wanted to see how heavy it was. Anyway my trailer has electric over hydraulic brakes and I was surprised how well it stopped. It certainly could stop quicker than my semi does does when loaded.
Yes having a strong truck with good brakes is important but the trailer brakes are just as critical. Even a semi won't stop worth a darn if the trailer brakes are not working properly.