I tow up to 11,500 lbs with a tag trailer and much more with a gooseneck and/or fifth wheel. If Dodge made a decent transmission I would agree with you...

The 48Re is an amazing transmission design. It is basically a 727 with OD. I had mine upgraded when I had it rebuilt. The fist time I took my son for a ride in my truck after the rebuild he asked why don't they make them like this from the factory? I told him money.
With a few upgrades they are great for towing. With all the good stuff they can hold 1500 hp or more. Some of the other brand diesels put a modified 48RE in their truck when they build extreme power because it is the strongest built modified diesel transmission.

My truck is at around 1400 miles now, and the mileage seems to be improving the more i drive it. I've been averaging around 14 mpg with local short trip driving.

I had to travel to Chicago for work yesterday, which was the first all highway trip with my truck. It was a 150 mile round trip on I94 in NW Indiana, and the Dan Ryan and Kennedy through Chicago. Rough traffic on the inbound trip, pretty smooth on the way home. I calculated the mileage at 17.2, the display showed 17.7. That's a bit better than I expected, especially considering the traffic.

My old 6.7 Cummins my have gotten a bit better mileage, but there are a bunch of other reasons a diesel isn't the right truck for me.

Then I guess I need to find the right rebuilder as the very experienced 727 expert I used really messed mine up! He didn't know how to install the overdrive apparently and it broke twice before I bought a new unit.

Not sure they use the mds lifters in the truck with the auto but they do help the mileage in my SRT. That would be a plus. My 06 diesel gets around 19.7 (3500 4-door) overhead is 4 mpg off. One issue after another with my truck, injectors just starting to mess up, too much electronics. I think the 6.4 would be the way to go right now, maybe the 5.7 with a longer stroke would be better but Dodge has there hands tied with emissions compliance. My 92 diesel went 200,000 and I washed it a few times. Don't they use the Allison trans now?