Andy tell me you are speaking from experience if not your opinion is just hear say.
Since we are going down that path all of the guys i have met towing behind the newer dual cabs don't have any issues with power. I have no doubt the 3litre is powerful though the new engines aren't just smaller they have better gear boxes to work as a better all round package, not to mention the Navara is twin turbo which means no lag, even when towing. The first turbo kicks in immediately and the second around 1500rpm the dealer tells me. As for the coil suspension Nissan is the only manufacturer doing this in this class and an airbag installed is 500 to 600 bucks which is nothing given the thousands of dollars people are filling their 4x's with accessories now a days. The other brands are leaf so if you want to save your $600 go with another brand. Even the guys driving coil sprung wagons are known to have the same issues but it's an easy fix.
I've just spent the last 7 years trialling at least 7 different transducers on my Cruise craft with an estimated cost of around $5k only now have I hit the mark and am happy, so $600 for an air bag; whatever. Need I say more.