Sorry for the necro, but I saw a link to this from XCF forum, and was intrigued by the idea!
I think this idea could potentially be quite interesting, and certainly make automatics far more valuable. This would be nice, but I'd like to throw a few ideas in.
-Damage threshold for initial check could be partially effected by bravery, and perhaps a little random. I doubt soldiers could precisely gauge a guns potency while bullets wizz past, so it would be slightly randomized, in my mind, and effected by bravery : This way rookies will be a little more likely to be pinned by small arms than those who have seen some action / have balls. Getting shot is never fun.
-I'd think pinning would effect stats some, like reactions and firing, I don't imagine a pinned soldier could fire accurately, or return fire as easily.
-Actual TU's lost, other stats lost, and kneel chance, I think could be again multiplied by bravery, so cowards are more prone to being effected a bit more harshly than someone who is brave. Even the bravest people flinch sometimes, but someone who is really scared of fighting aliens I think would freeze up a bit more.... this all might end up too heavily distinguishing the brave from the cowards though, I'm not sure. Regardless, stat hits to being pinned for aiming and reactions would be great, it was how xcom 2012 did it among other things, it reduced your aim significantly when suppressed
-Possibly an LOS limit on being pinned...wasn't this in xcom 2012? Make the players a little less visibly aware at distance due to worrying about being shot. Actually, this was technically for hunkering down I think, but this would effectively emulate hunker down panic from that if a low bravery check.
-Not sure how possible this would be, but perhaps an adjacent cell check on all 8 sides of the player, searching for a LOS break between the suppressor and the victim, and dependent on bravery, remaining TU, moving to said cell involuntarily.
-Make this also apply to explosives that blow within 1 tile. (1 tile from the edge, not the center obviously)
Sorry for the necro post again, but this was brought to my attention, and I really wanted to give my 2 cents into it...Hope it isn't a problem.
I'd love to see this added as a mechanic, considering I regularly use suppressive fire anyway to intimidate cultists (firing a mini-gun above their head) to delay a non lethal capture.
Also, forgive any of this being incoherent, I wrote this way late...