I thought about this as well. It all depends on the arc and how many each ftr gets. I'm not concerned much about Ftr squads or PF's being fired at by Ftr PlaD, I'm concerned about how lethal they are against drones. If you have seen what a StarHawk D Rom PF can do to a squad of mirak ftrs, it's rather scary. It;s more or less the same issue with ftrs.
If the ftrs all have 1 PlaD FH, I dont think there is much a problem... but still, 1x PlaD per ftr with 4x ftrs in a squad, that squad would waste 16 drones and reload twice, but is much less a threat to ftr and pf's, cuz they wont fire all at once.
I think it may be worth it to add 1x PlaD FH to a ftr squad and test them for balance. Mb give them a Ph3 FH as well. Remember, these are toally defensive ftrs and have no offensive ability. I like it better than giving the Plasma races the PhoF.