Well, you said you'd get back to my post about Zoroark but you didn't :P so I'll say it again.
Sorry, I completely forgot.
In the UU metagame as defined on this site, Zoroark is slower than 18 other mons which decreases to 10 counting only those in the UU tier. Zoroark's defenses are amongst the worst in the game (quick example out of many NFEs: Mienshao's pre-evo Mienfoo actually has only 15 less hp and 10 less in each defense than Zoroark). Also, thanks to those defenses Zoroark can quite reliably by KOed by a decently powerful priority user further adding to the problem of things outspeeding it which is compounded by its lack of 4x resistances and immunities.
I don't really see how any of this is relevant. It's outsped by a few Pokemon, but base 105 speed is still pretty fast in UU. Zoroark is a glass canon, but makes up for with an ability that lets it force switches or trick people into attacking with the wrong move, so I don't really see the issue here.
This brings us to why its other stats and move pool aren't enough. A pokemon like Zoroark needs to go before the other mon does and OHKO it, but it's not as common as its 105 speed stat might indicate that it outspeeds things and even if it does it will hardly OHKO anything without its offensive stat being boosted in some way, and in any case when that way isn't nasty plot + focus sash but instead a life orb, expert belt, specs etc. you open Zoroark up to being OHKOed by just about anything.
Zoroark has all it needs to succeed in UU. Between Dark Pulse, Flamethrower and Focus Blast it covers nearly everything you could ever wish to target in UU. I'll admit that Zoroark has trouble OHKOing threats because of its low base power STAB moves, but it has more than juice to 2HKO every conceivable threat in UU, which is relevant since if you correctly use Illusion you'll get a free shot in. I've moved away from using Nasty Plot sets since anything with faster speed can ruin a sweep and have since opted to use a Sub + 3 attacks set or stick Choice Specs for the free boost in power.
Consider prominent threats such as scarfcross, signifying a bunch of mons which "should" be outsped by Zoroark but in the reality of the metagame instead outspeeds it. This brings us to my next point which is that Zoroark's STAB is super effective against two relatively uncommon types but it has great neutral coverage. Neutral coverage however is better on bulky mons because they don't rely on OHKOing to the same extent that mons like Zoroark do which need all the speed, super effective hits and power that they can get to make up for not being able to take the return blow.
Again, I feel to see how Zoroark's inability to outspeed Scarf Heracross is relevant?? Are you trying to say that Zoroark isn't "fast enough"?? I think that being able to get jump on or tie with everything in the top 30 (sans Choice Scarf users and Raikou) is more than enough for me. When it comes to power, again I won't lie, it definitely needs hazard help if it wants to straight up kill things but I don't see the issue here, those are some of its natural limitations.
One last point of Zoroark's defenses is that you basically can't bring it in on anything except a harmless wall as not only will it faint, its only trump card in illusion will be broken if it takes a damaging move, Zoroark switching in on nigh anything is practically wishful thinking. Consider that even if you do disguise Zoroark as Heracross for example, you still need your opponent to switch so you can boost. This means that you must rely on what your opponent does and what mons he has available. Should you succeed, what you get is an easily revenge killed (particularily if sash is broken by stealth rocks) special sweeper relying on focus miss for coverage that still cannot OHKO neutrally hit bulky or defensive mons reliably to make up for being easily revenged - and as we already concluded, even defensive mons have what it takes to quickly rid the field of Zoroark thanks to its truly horrendous defenses.
You are not switching Zoroark into anything ever, save Mew (who kind of have no choice or it will rock your shit) Cofagrigus and the occasional Cresselia. You only switch with Zoroark when doubling switching, because if you switch into a Pokemon and take a hit (no matter how minor) you've basically just pissed away the best thing about it - Illusion. The assumption that Zoroark utilizes Illusion bluffs just to boost is faulty man. I almost never use boosting sets with Zoroark; I find that its best sets in UU are Substitute + 3 Attacks and Choice Specs. Sub eases prediction and lets you (usually) come out on top against the next switch in. If you've used illusion correctly, your opponent has brought in a Pokemon with the intent to counter your illusion Pokemon. (EX: You bring in Zoroark disguised as Shaymin, and your opponent either brings in Bronzong or Roserade in response). It's the strongest Zoroark set to use, and the most damage right off the bat imo. Choice Specs is still good (in fact I had a team that was designed around it) with Trick being your trump card (illusion can net you a trick on things like gligar if you use it correctly). I'm not sure why you're bringing up Focus Sash either, its always been kind of a gimmicky option on anything outside of leads in UU.
Which brings me to why I don't get why Mismagius is actually below Zoroark. Mismagius is a Zoroark that swaps illusion, flamethrower, focus blast (arguably not too much of an advantage anyway with the 30% miss rate) and 15 special attack for levitate, 45 special defense, a typing that completely outclasses Zoroark's and other coverage moves Zoroark doesn't get instead of flamethrower. Illusion isn't hard at all to play around imo and 15 special attack is just not enough to offset the major improvements that Mismagius gets in return. I think Zoroark should be in Mismagius's tier.
I think being able to at least threaten Snorlax with a potential 2HKO (or removing it while weakened) with Focus Blast / Low Kick and access to Flamethrower (which lets it break through Steel-types, Roserade, etc)
alone are reasons to use Zoroark over Mismagius. Dark typing also makes it less prone to Umbreon, and it can't be pursuited by Krookodile / Snorlax. Illusion is really just the icing on the cake. I think its a little odd to complain about Zoroark's relative lack of power when Mismagius is pretty much relies on boosting to get decent damage in, and even THEN it can't break through some of the better UU special walls.
I feel like a lot your post unnecessarily harps on a lot of Zoroark's obvious flaws and assumes that Zoroark's main sets often involve boosting of some kind, while neglecting to focus on its flaws. Yeah Zoroark has flaws that keeps it from being a staple (disappointing STAB damage and fraility) but it has more than enough benefits to hang with the B-tier Pokemon. The fact that Mew just dropped into UU should make this a no-brainer, since Zoroark is one of the very best Mew checks in the game.
I might actually consider moving Mismagius up though, since its a decent spin-blocker and it also checks Mew pretty well.