As I've retired from TKD, what the KKW wants then, now, or in the future is no longer my concern, so I don't really have a dog in this fight.
I was taught both lower (not TOO low, about twice shoulder width long) stances for stability and power AND high WTF stances for mobility and speed.
Being able to do both has served me well.
As training exercises, we would sometimes train a bit longer and deeper to develop strength. Doing a shorter, shallower stance was then "easy" and comfortable.
I fight from high stances — but if I ever need to MOVE someone with a punch, I can (and do).
And if I ever need to keep from getting run over, I can lower myself into a stable stance and keep from getting knocked down.
Whatever the official WTF curriculum demands, based on all the falling down I see from even the top rung WTF fighters, being able to do a deeper stance would surely come in handy, even if it isn't now — or was ever — required, official material.
It probably won't win WTF matches, but I would advise anyone interested in solid fighting technique to think about adding the ability to drop into a longer, lower stance to their tool box.