I've also been working with Steve Duck over at RCD for over two years about this same issue and they have developed a custom Bilstein shock that is designed specifically for air spring applications. I called upon Steve's input and here's what he had to say.
After spending the better part of 17 years in the aftermarket, hot rod and muscle car shock absorber industry, I was surprised to find out that a lot of vehicles were not running front shocks. At a show I came upon a beautiful '60s Chevy truck, 'bagged and sitting on the ground. After admiring it from a distance I took a closer look to see what kind of shocks it was running, but to my surprise, there weren't any shocks at all. How could this be, is there something inside these bags that damp the motion of the bag? I asked the owner how the truck rode, "great on a smooth road" was the answer. Well, in a perfect world, with only smooth roads, that would be ok I guess, but this is not a perfect world. How many of you have been driving down the road watching a wheel bounce off the pavement or felt the chatter of the car going around a corner as the suspension is upset from hitting a bump in the road? Bottom line is whether you have a vehicle with air, coil, or leaf springs a shock is necessary to control it.
Now, I have never been someone that tries to baffle people with engineering and numbers crap, so let's just start with the basics. A shock absorber's job is simple, it controls how fast the spring (or air spring in this case) compresses and rebounds. When hitting a bump in the road you want the suspension to compress absorbing the bump, the shock slows this compression motion down so that the tire can return to the ground quickly and get back to its job of holding the vehicle off the ground. How fast the shock slows the wheel can determine what you feel in the vehicle. If the shock has too much compression rate slowing the movement down too rapidly, it will translate into a harsh or jarring ride. On the other hand if it is has too little the vehicle will dip/dive and have less control when cornering. The opposite motion is rebound; this controls how fast the spring expands. Not enough rebound rate, feels as if you are getting pitched out of the seat and there will be a lot of upward body motion. Too much rebound rate and the vehicle will feel like the rear end is kicking when going over bumps. Often this is hard to differentiate between too much compression and rebound in the rear.
To get the best ride quality at RCD we set up our Bilstein shocks with valving that slows the compression movement, keeping the tire planted on the pavement. But the rebound rate can be 2-3 times more aggressive to control the expansion of the bag, this helps to settle the car quickly after hitting the bump. That said, just because you have a shock on the vehicle doesn't mean it is the correct shock, but having the wrong shock is in most cases better than no shocks at all.
I feel much better now after consulting the experts, knowing that it's not just me and that I'm not going crazy! Hopefully after reading this you can see how shocks not only offer a better ride in almost every case but can make the vehicle safer as well. If you're still not convinced, try shooting yourself in the stomach and see how that feels. For more information, contact the companies listed in the source box.