posting on behalf of molk, he wrote most of it
Furthermore, Nidoqueen's pure offensive might discourages slow, bulky Pokemon such as the one's c_l listed: Steelix, Tangrowth, Ferroseed, Roselia, Amoonguss, Lanturn, Regirock, Flareon, Qwilfish, Garbodor, Poliwrath, Mandibuzz, Rotom, and Miltank, as well as slower Pokemon in general like Crawdaunt, Bouffalant, and Aggron.
Out of the Pokemon you listed, all of them are affected by Nidoqueen's presence. However, this is not to say that Nidoqueen's abiltiy to OHKO hinders them from doing their roles, or indeed that Nidoqueen can easily switch in. In many cases, Nidoqueen itself must be wary of switching in lest it suddenly be in an unenviable position.
(Ferroseed and Mandibuzz are not commented on because the former is threatened by Fire moves, Queen or not, and the latter sucks anyway)
I've seen Steelix being used effectively in this metagame even with Nidoqueen's existance. The Nidoqueen player has to be wary when switching directly into Steelix because a 0 Attack Earthquake does major damage to her as she switches in, which has been quite the annoyance for me on occasion when i really have to take out a Steelix.
Ive also seen Tangrowth used effectively in this metagame as well, Sleep Powder is usually enough to keep Nidoqueen at bay at least temporarily, and even after sleep clause is in effect , Nidoqueen has to be wary of moves like Earthquake, Stun Spore, or hell even Leaf Storm (I remember Double01 doing pretty damn well with a Life Orb Tangrowth during Cresselia metagame and on). Even Leech Seed will harass Nidoqueen as the lost HP it cannot gain back, and it will heal up a special wall coming in the Nidoqueen could potentiall 2HKO otherwise.
Roselia is still more than viable in this meta despite its recent drop to NU, it's still an effective Spiker and its one of the most solid checks to dangerous Grass-types such as Sceptile and Lilligant. Amoonguss is in the same boat, except it gives up Spikes for Spore, Regenerator, and a significant amount of physical bulk.
I dont see how Lanturn is hindered by Nidoqueen's presence either, its still one of the best checks to dangerous Fire-types such as Entei, Magmortar, and especially Moltres, and it can support its team well with its slow Volt Switch and access to Heal Bell. Nidoqueen isnt going to enjoy switching in on Scalds, especially because of that high burn rate.....Furthermore Lanturn can still adequately pivot around Nidoqueen for a Stall or balanced team, as its typing discourages the use of Thunderbolt or Fire Blast as options, allowing a teammate such as Cryogonal or Slowking to come in with lessened risk.
Regirock was hardly ever used before or after Nidoqueen arrived. That said it is a potential member of stall and Nidoqueen does discourage its use. Regirock can also threaten Nidoqueen with Earthquake, which will 2HKO, should it choose to use that as coverage, meaning Nidoqueen cannot necessarily switch in for free.
Flareon was already a terrible Pokemon before the introduction of Nidoqueen, with its only real niche being countering Moltres, who can 2HKO it with Hurricane after Stealth Rock. I don't see how making a previously mediocre Pokemon a liability is a problem.
I've actually been using Qwilfish quite a bit recently, and i cant see how you could call it a liability at all, its a great check to other common threats such as Durant, Escavalier, Entei, Smeargle, etc. It's naturally good Speed and Attack make it a good choice on many teams, and its Waterfall will also discourage Nidoqueen from switching in lest it be hit for more than half its health, not to mention that it can be EV'd to Outspeed Nidoqueen (i regularly use enough speed on my own Qwilfish to outpace opposing Smeargle so i can taunt it), further discouraging Nidoqueen from switching in. Qwilfish also sets up Spikes that hinder Nidoqueen's ability to switch in for free.
Poliwrath may be severely threatened by Nidoqueen but is no less viable for it, being one the best options to many of the most dangerous physical attackers in the tier, including Durant, Entei and Aggron. Indeed, Nidoqueen can hardly switch in on the standard defensive set, as Scald will deal heavy damage as well as possibly burning it, whereas Circle Throw will deal chip damage in addition to the Stealth Rock damage Nidoqueen must then accrue again.
Ive also been using regular Rotom lately, and while Nidoqueen does make his life harder, ive still been getting a lot out of using it. Its typing is still phenomenal, granting it 3 immunities taking into account levitate along with a ton of resistances for it to switch in on. Shadow Ball can 2HKO Nidoqueen if re remember the formerly popular SubSplit Rotom set, and HP Ice is viable on a Choice sets, though the Choice sets are undoubtedly worse off with a storn Electric immunity in the tier. Rotom is also your best bet if you want to stop Kabutops from spinning using its bulky set, which is a great niche in and of itself.
Ive seen Miltank in action rather recently and i can say for a fact that its still very viable even with Nidoqueen around. Its a major annoyance to hail teams with its thick fat ability, ability to set up Stealth Rock, and reliable recovery combined with an excellent base 100 Speed stat. Miltank is also very good at running an offensive set that carves a niche for itself as one of the best checks to Grass-types such as Lilligant and Tangrowth around.
Crawdaunt, Aggron and Bouffalant don't particularly care about Nidoqueen unless their in on her in a neutral situation, as Crawdaunt will have either Substitute or Dragon Dance to benefit it, whereas Aggron is able to have Rock Polish or its own Substitute to hide behind before Earthquaking. Nidoqueen can't switch in on either of the pair safely, except on Aggron's Head Smash where it will still take heavy damage. Bouffalant doesn't give two fucks when it fights Nidoqueen as long as its not switching in, its huge bulk ensures it can take one of Nidoqueen's attacks and hit very hard in return.
Nidoqueen strongly discourages the use of these (previously) good Pokemon, causing less diversity among the tier. Accelgor, Galvantula, Scyther, Manectric, Magneton, Hitmonlee, and Klinklang and Primeape to an extent have all become worse due to Nidoqueen. There is barely a reason to use any of those Pokemon with Nidoqueen in the tier.
Accelgor can 2HKO with HP Water yadda yadda, will often Spike as its goal anyway yadda yadda this has been discussed a fair amount.
Galvantula is no longer as effective as it was with its Electric STABs neutered but is still effective in the metagame, and is capable of 2HKOing Nidoqueen with a SE HP Ice.
Scyther was hardly ever used before or after due to Stealth Rocks, Nidoqueen had no effect on it. Further more it 2HKOs Nidoqueen with Aerial Ace, discouraging an opposing switch in.
Manectric is no longer viable as a Choice Scarf user due to Queen, though I have heard good things about its Life Orb set.
Magneton's goal is to trap Steels more than spam Volt Switch, and heavy damage can be dealt with Flash Cannon should Nidqueen switch in. Magneton was hardly considered a top tier mon before Queen was introduced either.
Hitmonlee dgaf about Queen. Never OHKOd by Sludge Wave without a crit, deals heavy damage with Earthquake, this matchup is even, if not slightly in lee's favour.
Klinklang was always a Pokemon that required team support to be effective, and loved Spikes, and Nidoqueen is no different. Nidoqueen hardly affects the way Klinklang plays at all, and its usage was lacking both before and after Queen.
Primeape was likewise never considered particularly good, and its role as a fast U-Turn user has not changed with Nidoqueen's introduction. Nidoqueen only discourages Primeape insofar as its ability to take its STAB attack with relative comfort.
In short, while all of these mons are affected by Nidoqueen, perhaps discouraged in use, this does not make these Pokemon unviable as they are all still easily capable of performing their role, and in many cases threatening Nidoqueen in their own right. In terms of the offensive Pokemon listed, half of them barely have a reason to be used regardless of Queen, while the other half suffer comparitively little effect from Queen's presence. In terms of the defensive Pokemon listed, the majority of them discourage Nidoqueen from switching in through their own moves or STAB, and often require a specific move to be used in order to KO them which allows for a more specially defensive teammate to come in, without Queen having prevented the defensive threat from doing its job in the first place.
EDIT: Molk on TR
There is barely a reason to use any of those Pokemon with Nidoqueen in the tier. This also excludes the fact that Trick Room teams, which at a time, were incredibly viable, have become nigh unusable, simply because of the ease at which Nidoqueen destroys slower teams.
This is not true in the slightest, to be honest. I had been using a Trick Room team that i made in BW1 for quite a long time, i used it both on the ladder and as one of the trainers in the RUgged Mountain challenge, and i never really had a problem with Nidoqueen. Two of the best Trick Room setters in the tier, Uxie and Mesprit are already recognized as some of the best checks to Nidoqueen in the whole tier, which makes it much harder for Nidoqueen to trouble the Trick Room team. Also, most of the Pokemon on my Trick Room team were more than bulky enough to take a hit from Nidoqueen and were all capable of doing serious damage in return and/or setting up Trick Room. To be honest, the only reason i stopped using that Trick Room team in the first place is because Cofagrigus moved up to UU, and it was a crucial part of my Trick Room team, or really any Trick Room team for that matter.