You guys do realize Alex already tried DatonKallandor's suggestion and ruled it out, right?
That would be incredibly strange, since the current implementation is weird at best - it screams placeholder and experiment.
It's two different versions of trying to do the same thing, implemented on a wildly varying (in terms of role and performance), tiny subset of missiles. There is nothing logical about which missiles got the regenerating ammo and which didn't (and which got one version of regenerating ammo and which got the other).
Pilums, already one of the best missiles and one of the few to use a meaningful cooldown to limit it instead of ammo - it's ammo reserves are huge compared to other missiles - got higher fire rate than ammo regeneration treatment.
Salamanders, another of the best missile types which was hard ammo limited, with a fire rate that was so fast as to be meaningless (the opposite design framework Pilums had) got the fire rate adjusted and the ammo system removed entirely.
Hurricane MIRVs, one of the worse missile types but which benefited outrageously from missile ammo skills and then became pretty good got the Pilum treatment.
Yet no other missile was touched, despite many of them sharing the same fundamental problems (or lack of problems) of the missiles that did get regenerating ammo.