In 2009, there was a huge policy debate about changing the outcome of matches based on "more skillful play" to eliminate losses based on severe luck.
It turned out to be a giant April Fool's prank. I recommend reading through the script; it's pretty fascinating, and hilarious to see the "roles" that both contrived and genuine forum posts tend to gravitate towards.
In your case, while the statistics themselves are objective, interpretation of them is not. If I Mist Ball exactly once and get the drop, is that hax? Or would it be hax to not get the drop? If I use Iron head twice and it flinches once, is that hax? That's a 50% flinch rate, but it's as close as possible to its innate 30% chance, so should it be considered the expected outcome or 20 percent higher (or 50/30 = ~67% higher?). Moreover, not all instances of hax are equally impactful, or can even be subjectively impactful—a crit on a move that already KO'd wouldn't matter at all, and a crit dealing 90 instead of 60 might not matter since it was a 2HKO anyway, but it could have impacted the decision not to switch due to being in Stealth Rock KO range etc. Trying to create a formula that accurately measures luck and applies an outcome to your ladder ranking is nightmarishly complex and subject to endless argument.