On hax items, one other relavent aspect I feel like hasn't been mentioned that goes towards the competitiveness of it all is predictably. Like with rockslide aero or serene grace, etc there's only a certain number of pokes that can run them, or make them viable, and you can at least expect your 30% chance or plan for it when you see them and build strategies to counter it. Even the with the 20% evasion, this is true. But with hax items, now all of a sudden anyone can flinch you with anything, and things like rhydon can have priority where they shouldn't, and an otherwise well set up, and perfectly planned sweep can fail because your 100% hit rate didn't hit. Yes, it's only a small chance that you're dealing with, and usually better to run something else....I agree...but it does kindof go completely against the whole strategy of it, which is annoying.
Perhaps you could make the same Arguement for crits, but at least they can serve an established purpose in terms of things like making leaf blade more viable, or focus energy + scope lens, or breaking past curse setups, sniper, (that move they just added that stops them I forgot the name of), etc.