Not sure of the physics end of things, but wouldn't the air bags lifting the rear transfer some weight forward ? instead of the truck sitting nose high without the bags and level with the bags.
Imagine a wheelbarrow with 10 foot handles, would raising the handles an inch or two do much?
The idea with the WD is to keep the front axle from unloading with the trailer on the hitch. Unloading 25 or 50 lbs isn't the end of the world, one or two hundred and you could start getting understeer.
I have a 5er with the pin 4" ahead of axle centerline. Bags took all tha bounce out and made it ride better off the overloads. Pin wgt is 1700+ trailer losded is over 13K. Have the comp with cab controls. VERY good investment. Rig handles like a dream. And is very handy hooking and dropping.
04 Tail gator XT 34' 5th wheel garage model
99 F350 CC DRW 7.3 ais intake, adrenaline hpop, JW valve body,
cooling mist water inj, DP tunes, 4" turbo back exh sys
trucool trans cooler added
08 Arctic Cat Prowler 700XTX
From what I can remember from racecar setup airbags should transfer some weight forward.
I setup my WD hitch to get my front end sag back to or slightly below unloaded. I can tell you it takes a lot of doing to get the bars up that tight (1400 lb bars) but it seems to handle well like that.
My front end is about a quarter inch below unloaded and my back end is down about 2 inches from unloaded.
Airbags are good in some applications. Just remember that they don't increase the overall axle rating or the tire rating.