Of course lets not mention that a coil spring is much cheaper to manufacture than a leaf spring pack is and that coil springs have absolutely no rebound damping and are thus wicked on shock life, whereas a leaf spring pack has built in damping due to the inherent friction between the leaves.
I'd say it's more of a cost saving measure on the part of Fiat-Chrysler than any other reason. Gotta keep that P&L statement well on the P side.
For truck use (other than getting groceries or hauling a couple bags of fertilizer), coils suck, plain and simple.
Show me any vehicle with coils springs (on the rear) after 20K of American roads and I'll call it a pogo stick on wheels.