I don't know if this has been mentioned, but the idea of using Low Kick over Superpower is something I've tested a bit to fairly decent success. Because honestly, Superpower is there for coverage or a last-ditch effort to nab a KO, and why not use a fairly similar attack without the stat drops? Stone Edge is the better option for Pokemon like Scizor, and Pokemon like Ferrothorn, Tyranitar, and Terrakion, the Pokemon Superpower was designed to hit, will be taking similar, if not equal damage.
Superpower:
CB Tyranitar vs 252/88 Ferrothorn = 92%HP - 109%HP
CS Tyranitar vs 252/88 Ferrothorn = 62%HP - 73%HP
CB Tyranitar vs 4/0 Terrakion = 149%HP - 175%HP
CS Tyranitar vs 4/0 Terrakion = 99%HP - 117%HP
CB Tyranitar vs 252/0 Tyranitar = 100%HP - 118%HP
CS Tyranitar vs 252/0 Tyranitar = 67%HP - 79%HP
Low Kick:
CB Tyranitar vs 252/88 Ferrothorn = 77%HP - 91%HP
CS Tyranitar vs 252/88 Ferrothorn = 51%HP - 61%HP
CB Tyranitar vs 4/0 Terrakion = 149%HP - 175%HP
CS Tyranitar vs 4/0 Terrakion = 99%HP - 117%HP
CB Tyranitar vs 252/0 Tyranitar = 100%HP - 118%HP
CS Tyranitar vs 252/0 Tyranitar = 67%HP - 79%HP
Basically, because of Low Kick's mechanics, they do roughly the same amount of damage, bar against Ferrothorn, where the attack and defence drops will become noticeable, as CS Tyranitar may not even be guaranteed to 2HKO after one drop. Since the damage mechanics of Low Kick depend on the opponent Pokemon's weight, where I'll add that at the end of this post, it only seems reasonable, as it allows Tyranitar to stay in longer and do more damage over a longer period of time. Hell, the increased PP is a nice addition too. The only downside is against things like Lucario, Magnezone or Scrafty, where the base is 80, 100, or 60 respectively, whereas Superpower is 120. Seeing that those six (Ferro / Terrak / TTar / Luke / Mag / Scrafty) are all Superpower is really designed to hit, I don't see why it shouldn't be considered.
Low Kick:
<22lbs = 20 Base
>22 lbs, <55lbs = 40 Base
>55lbs, <110lbs = 60 Base
>110lbs, <220lbs = 80 Base
>220lbs, <440lbs = 100 Base
>440lbs = 120 Base