Wait wait this F+K nerf... it's not in the patch notes. How many frames is the stun now? Can it be slow-escaped?
You could always SE it, just on fastest SE it would only bring it down to like 26 frames if I remember correctly. They nerfed it to where it is now 21 frames on fastest SE meaning he no longer gets a guaranteed CB. He also doesn't get the sit down stun in neutral anymore. It just does the crumple stun when they bend over and hold their gut.
You can chain 3k into it, but its kind of pointless as 3k pushes them so far away that you get nothing out of it because they can SE and block 66k. If you're near a wall and f+k doesn't wall splat first then ya 3k is handy because you get a guaranteed wall splat. Really the setup seems designed more for tag than singles currently.
1p is also no longer guaranteed from the sit down setup. You can still get 9k launcher guaranteed, but a lot of times the stun pushes them to far away from it so 9k just whiffs, and if you dash forward they will have SE'd and blocked by then. They also nerfed the stun length of dragon stance 6p and dragon stance p. DS 6p you couldn't SE and block 4f+k or f+k. Now you can SE that stun easily. DS p you can't SE fast enough to block them, but 4f+k puts them in a weird angle and you can't launch with 7k(and 9k launches so low that all you can get is 6pk or 6k46k) and f+k after DS p doesn't put them into max critical like it used to and it pushes farther away for some reason so all you can get is 66k. So basically his options in DS are more limited now. If you want to get 4f+k during the DG setup you pretty much have to do DS k to get it. Anything else you are just playing a longer stun game (/wrist).