In the automotive industry for 16 years, live in Colorado. My vote is gas with the right gears. Too many diesels with the exhaust fliud stuff spend a lot of time in the shop.
Will a gas 2500 chevy pull better than your 1500? YES, chevy detunes and gears the 1500 for mpg.
Tundra with the 5.7 6speed auto and 4:10 rear is a beast for towing. Rest of the truck is so so for handling.
Ford with the ecoboost has instant and constant torque. Don't buy the '15 or newer made of aluminum, insurance is high for repair costs.
Dodge, well don't go gas that hemi doesn't like pulling a load unless you have 5:56 rear end ratio. I do business with a major dodge dealership and they won't keep a 2500 with a hemi, sell them at auction.
The f150 has the most towing engineering for a half ton. Even without the ecoboost it will be a great balance for towing and daily driver.