I think that leaves 7K/Flamingo K and 66K/Flamingo 6K as his Sit-down stuns now and they're both on crouching or on CH only. I'm sure as not that happy with that, but he still has two sit-down stuns (kind of a shame since they're both mid-K and it can hurt his mix-up options) and you can still probably get a 8KK or something similar from the new bound.There aren't that many Rig players out there. I think I've run into one good player that mains Rig (Jaeger) and maybe 3 others (Including myself) that can even use him.
On topic, I don't remember where but I saw 7P do a bound effect. Presumably, the bending stance version will do this as well. This is undoubtedly a nerf because it removes a sit-down stun, and it could be potentially worthless outside of tag.