3/4 and Full Ton trucks already offer shoppers big time power and capability. A 1/2 ton trucks suspension and chassis was never designed to handle the type of loads the 5.0 Cummins is capable of tolerating.
Towing is about more that power/torque figures right. I just don't legitimately see a half ton chassis being robust enough to tow say a fifth wheel trailer, regardless of what your engine can do you're only as capable as your weakest link.
To take full advantage of the Cummins ISV I think Nissan needs to:
Strengthen connections between suspension axles and frame
All of that will simultaneously add weight and cost to the Titan. The second question then becomes is will Nissan simply strengthen the relevant components for just the ISV Titans or will the new measures extend to the rest of the Titan range. If they do what sort of effects will they have on Gas Titans? The increased robustness would be superfluous in a gasser, sure its nice that they are overbuilt but again at what penalty?