The classic AIR valve uses velocity controlling regulated air at the top of the on-off pin unlike direct tank pressure at the pin of a retro valve. The reset action of the retro pin in an AIR valve has the same starting force as a stock AIR valve on-off pin. The smaller diameter of the lower section of the pin means your trigger pull force will be half of what it is with the stock pin. However, the differential force between the trigger pull and return force is significantly lower on a classic AIR valve compared to a retro valve such that even using a retro on-off assembly will not result in reactivity at the trigger.
Except for the Automag in front, its usually the man behind the equipment that counts.