I can't really think of anything I want for her besides a tracking 3K and her SS P+K being similar to Akira's. She's already pretty good because she's so safe and has great options for whiff punishing.
After thinking about it for a min, I really would rather she have a mid that's similar to H+K (but I'd rather it guarantee some sort of damage in both stances) but slow-ish at 21 frames or so.
6P+K stunning on NH was always dumb (she does not need that braindead bs), heichu doesn't need to track as working around non-tracking with delays / throws is a big part of playing Kokoro, and since she's not a sabaki / parry character I think her having a mid sabaki that gives you a 1 guess CB would just be another example of chars getting stupidly good tools they do not need.