Well, I can't seem to find whatever post I remember reading regarding STOs. It also seems that the discussion I found from back in August regarding someone doing a Flak Suppression mission against an NPR resulting in all of their fighters blowing up without doing anything seems to be functioning correctly? At least, if I'm reading it right, the mission they chose would result in their fighters choosing a random hostile formation and, if it has no AA, proceed to do nothing. In turn, every single AA unit fires back at them. No wonder they just got blown to smithereens without doing anything.
If nothing else that means that STO as far as I can tell cannot be used to target ground support fighters, and that the non-support missions aren't bugged. That just leaves the direct support assignment being tedious (has to be done per-craft, so... lots of dragging, if you use them in any amount of volume), and non-support missions being of dubious benefit (you're gonna need some seriously fast fighters to not just get blown out of the sky). So... potentially useful but mostly tedious?
EDIT: Actually, thinking about it, I don't think they're too unreasonable to use in the right circumstances. The times that you're going to want large volumes will be defensive, in which case you wouldn't assign to individual formations anyway; just set them on a mission to bomb any enemy and due to numbers they'll pretty easily overwhelm whatever forces they have. Offensively, you'd want to assign them to supporting a formation as an anti-air to take out enemy bombers (since they won't be able to be bombarded due to not being a ground unit, and retaliating as anti-air as per the mechanic against non-support missions where every anti-air is triggered against them) since in any other position they'd just be blown to pieces by the defending forces' overwhelming amount of anti-air fire.