I've owned my Tundra for over 6 years and wouldn't give it up. My TT is the same gross weight as yours. No issues towing; yes it will go to 3500+ rpm on a longer hill, but that motor red lines at around 5600.
Towing mileage around 10 and 17-18 highway. It has almost 60k miles and has only had oil changes and one set each of brakes and tires.
I suppose the only thing I might want to change is the slight bounciness when towing on uneven freeways. But I don't do that much so not a big concern right now.
No one condones going over payload, and it doesn't sound you like you would. But the components in the Tundra are at least as heavy duty as a Ford rated for more.
And as mentioned, the new ones can have the larger fuel tank, brake controller and tow mirrors from the factory.