There's lots you can do to improve "towing experience/safety/comfort".
What tires are on this rig? If they are P passenger car tires get some good LT tires, load range D or E. Do you have a transmission temperature gauge? That would be a great addition if you don't have one already.
Is the hitch the OEM unit with the round tube? These were known to have some problems with cracks at the welds. A good aftermarket hitch would be a great idea.
You'll need an electric trailer brake controller. Don't get a timer based control. Get one that is momentum based, the braking action is much smoother.
Axle and transmission swaps are probably not a great idea. A 1500 Sub. is pretty limited in the payload area already. I wouldn't go crazy trying to modify it to become something it's not. Start saving for a 2500 model.