I believe you could easily get the PhGs selectable by first selecting all weapons, then deselecting the ones you don't want grouped with them (maybe even all other hardpoints), and then assigning them a hotkey.
On the Plasma, Fs are nearly useless in an X vs. X fight -- they're too fast to hit with Fs because of the limited range and drop-off in damage. Droners don't have that damage reduction, and their drones fly for much longer. Also, I wonder about plasma D BPVs according to SFB, since there they could be used offensively, right? Here they can't.
I also agree that PhG are a tricky issue, because they are so good offensively. I still like the Ph3 as an option, though it has plenty of flaws, too.
What I'd really like to hear is more opinions, especially from players with a lot of flight time. It's all academic until it plays out in a match.