I dont play sub-zero, and never had much thought about his ice clone being "too powerful" in other games - it's basically one of his most defining moves. In MK1, I can unbiasedly say his ice clone is so laughably worse than every other version that you can teleport ON REACTION and punish it, 100% of the time, if he does string into clone (at least with Mileena, whom I play a lot). They should make the recovery frames way faster and have it last AT LEAST half a second more, IMO.