I had to add a longer stinger on my Equil-izer hitch, as I have the 4x4 CTD and it sits really high on the back. As others have said, without the WD hitch the trailer bucks on the highway, and the hitch makes the ride much smoother.
As to the coil vs. springs, the one drawback of the 2015 2500 and its coil suspension is that Dodge now advises against heavy cab-over campers, as the coils cannot handle the weight on the bed the way the leaf springs can. I think you have to go up the 3500 if you have one of those really heavy cab-over campers with extensions. Not all dealers are aware of this, though the owners manual is quite clear on that point.
I thought I would prefer a coil over suspension, but the leaf springs, when fully loaded with the AS, ride just fine.
2014 28' Flying Cloud
2013 Ram 2500 Laramie Crew Cab CTD 4x4