I suspect moves like this existed as a roundabout way of balancing variations before we got customs. They aren’t supposed to be better than the moves they replace...they were intended to prevent the use of strong base kit moves along with certain strong variation options.
Jade reflect, sub shoulder, and Kitana razors (tho this one ended up being really good), all replace great base kit moves and are also paired with great other custom tools (Deadly assassin, amp ice ball, and Half-blood stance). I’m sure there are other examples.
Of course I don’t have any actual proof of this theory, but I’ve seen devs balance games like this before. Khanum Dash was probably meant be paired with something the devs were afraid of being OP like Vanish.
The thing is the balancing fails when the moves are so inferior to others that it is nigh impossible to justify them replacing something else. Mileena was made around with Ultimate and customs too. I understand that balancing concerns are real and valid, but we've had time to contextualize it and the move cannot be justified replacing ball roll in my humble opinion.
My point isn't that they have to be better, my point is they should be able to justify replacing another. An example of a move being good replacing/justifying another is Baraka's spine burst replacing chop chop. It's a trade off but the anti-air and safe chip capabilities justify the tradeoff even if I personally prefer having chop chop, I can objectively say, "this is my preference, but this option is great too and worth utilizing even if I don't".
Take it a different way. I can justify equipping Jade's additional strings or her low spark or pole vault, Pole Slam, anti-air glaive , amp shadow kick so I have roughly 5 choices for a third variation move that I could justify as being worthwhile and crafting different builds.
If a move is good like razors were/are then that's something where even if you don't like it, you can contextualize why someone else likes it and uses it. It gave her a safe meterless chip tool, high unbreakable damage and a 50/50 standing scenario so with that being the case you can justify losing lift ombos for a move that does so much. If Kahnum dash was as good as razors were/are I don't think it would take much to sell people on it.
TL; DR:
A move replacing a base move is not the issue. A base move being replaced with a very weak or underwhelming move simply cannot be justified as being worth equipping. I've listed a couple different examples for Jade, Baraka and Kitana to illustrate the core points and ideas.
I'm a pretty big fan of the worth of MK11 Mileena, she has a suitable and sustainable tool kit.
