The new Ecoboost has plenty of power for my camper but there is some bounce when towing it.
This is likely because you are wayyy over your payload of the truck. That's just a guess but a 5th wheel on a 1/2 ton is a bad idea unless it's a really light one. That's a very different number than the EcoBoosts tow rating. The truck will move that weight, but safely is completely another question.
But to answer your question, airbags will allow you to "level" out your load, and should help with the bounce some. But in truth, it's gonna bounce some, it simply won't ride like it will when not loaded. I had bags on my last truck and they helped some, but I am also bumper pull, so that's a different problem altogether