That will certainly lower the trailer frame to the boat axles, picking up a few inches.
However, I'm impressed with the torsion springs/axles of the EZ-Loader trailer under Journey On. This is great improvement over the old leaf springs. There just isn't much room to lower the frame until the cross bars start dragging. Time does march on.
Sounds like it might be a bit complex and expensive--with an air compressor involved. It would have some applications--sure be nice to get the boat nearer to the water at launch. Of course you have to raise the fenders.....as you lower the frame....
If you could get the frame low enough you wouldn't need to back the trailer in as far as usual, which might keep the bearings out of the salt water. Over time, some of the higher initial price would be offset by the reduction in maintenance.