In my experience, flashbangs are about as useful as a pee-filled balloon. I have seen them work as intended exactly twice, and that because they blew up right in front of an ortnok, as in, point-blank range; other than that, they have done little else than annoy whatever I throw them at, and that's when they don't just get a "return to sender" courtesy of the soldiers' poor aiming with throwables in general.
IMHO flashbangs need a complete overhaul to be an actually viable weapon because, as they are now, there is no real reason to use them instead of the later-plentiful plasmas or the plain, old frags. Concretely I see they need:
-First of all, make them actually work.
-Larger effective radius, with diminishing returns past point-blank range (for example, past 5 tiles units lose 5 TUs less per tile away from the explosion).
-In later game stages, add a research that projects an EMP from the grenade, so it affects robotic units. If testing deems it too overpowered, make it two separate grenades, one flash, one EMP.
As they are now, flashbangs are just a notch above picking a rock off the ground and throwing it at the aliens.
