I added PacBrake air bags to my 11 Dually only for helping control the chopping you get on some highways. I also added Bilstiens at the same time, The ride was much better. Can't say for a fact what made the ride better, probably both items equally.
As far as Factory air bag failure I would not worry about it in the least. Don't think the Semi's worry about it.
When they become available next year there will be one on my driveway, of course with all the gaudy LongHorn stuff!
Anyone looking for a nice 11 HO Longhorn Dually?