Calculus isn't confusing :/
Salamence should have stayed in OU because sandstorms are far more common than any other tier (Sure you can use Tyranitar in Ubers, but when there's Rayquaza it means nothing). Hard counters for each set did exist, and a Hippowdon EVed correctly could have countered both DD Mence and Mixmence (Barely surviving two Draco Meteors and surviving a +1 Outrage on the same EV spread is beast IMO). It was the same as Garchomp but worse; did Garchomp have the SR weakness? Of course not. Did Salamence have dual STABs to abuse? Obviously not, and if I see a Salamence running Aerial Ace I'll have to bite myself to make sure I didn't read that wrong. Setting up Salamence required you to almost always have Magnezone support, and that's become one of the most obvious combinations which is often easily stopped by simply U-turn spamming.
Mixmence, I admit, had people screaming foul play, but I doubt even a max defense Bold Blissey would have been 2HKOed by the New Mixmence's spread of 16/240/252 Brick Break, even when backed up by a Life Orb. So, Blissey was actually the full stop to Mixmence providing the correct defense investment (Which is common). It's not like Garchomp; you didn't know what set it was, and you could lose games unless you ran multiple counters for one Pokemon to each set. Scizor still held up as a Mixmence counter, since indeed it could survive a Draco Meteor the same as it could survive a +1 Outrage. And for both sets, I'm not even going to start on Weavile and Mamoswine.
Sure, there are indeed loads of other Salamence sets, but all others have flaws that are shared by the two I mentioned. Just because Salamence had brilliant offensive stats doesn't mean that it was too good for OU; in fact, I'd say that those offensive stats costed it bulk. 95/80/80 defenses are not bad. But they are not good, either, and Intimidate only works when you switch in. Heracross has comparable defense stats to these, and doesn't have Intimidate, but it doesn't have the same switch-in opportunities; rather than physical attacks, you switch it in onto a status move! Obviously this activates Guts and turns it into a far more potent attacker than Salamence with those dual 120 STAB moves (Whereas Salamence only has one true STAB to wreck the metagame with). If they banned Salamence partly because of Intimidate giving it "bulk" then they should ban Heracross for its "overpoweredness" after Guts kicks in!
I disagree with some of these statements because for one once you know what the set is your either A. About to eat a basically +2 outrage/earthquake that 2hkos everything in the metagame besides obvious scarm ,fortress i think (dont feel like doing calcs), or a Draco meteor thats arguable very very very close to latias specs draco meteor. And then eat another one of his moves if he feels like it and if you dont have SR up your fucked and you should just quit the game.(an exaggeration). Using things like hippowdon and blissey just to counter a top threat is not cool. Breloom loves to step in and fuck blissey's mom. Once your created "hard counter" is shown a "hard counter" to your "hard counter" is going to eat you alive for example Hippo to breloom.