SOS 2 isn't a hard knockdown, and after playing Gunslinger exclusively I've had nothing but SOS 2 whiffing on jump ins. The risk-reward is so bad with this move if all you get is a measly 10% and a normal knockdown which guarantees no type of pressure midscreen. If you read a jump in you might as well just cancel out and do your standard uppercut AA which does more damage. This move seriously needs a buff in order to have any type of utility.
Oh its not a hkd? That sucks, it definitely needs some buffs then.
I did some experimentations with it earlier today, turns out it has a very thin hit box and can barely be used as a combo ender as a result (it only connects after b2...)
So as it stands:
You can't follow it up, it doesn't hard knock down and even if it did it doesn't even have the frame data to be used for the exact purpose it is designed to be used for! (You can't whip it out on reaction and it offers nothing of note over d2, making the latter his best AA full stop)
I used to be of the opinion that since he gets 3 options off SOS, 2 not juggling wasn't an issue. Not any more, it's practically useless.
The only thing it has got going for it is it's a diagonal upwards (~30 degree angle) AA...oh and unbreakable combo damage off of b2(!)
I dont know exactly what buffs Gunslinger needs (I need some time to think things over and see what does he actually need), but I am now convinced it definitely needs something.