It's funny, it seems these days when it comes time to vote for a suspect I have little to say, having put it all out there on the forums or on irc already. But I'll reiterate some of the points so far that have led me to my decision on Nidoqueen. Despite being an amazing special attacker, Nidoqueen is not broken, as she neither inhibits diversity nor requires extreme countermeasures to be taken to beat her. Many arguments have been made about how Nidoqueen destroys stall and balance teams, however, I believe that both playstyles are capable of being used effectively, and that decreases in Stall's utility is not solely a function of Nidoqueen's presence in the tier. Nidoqueen is the best Pokemon in RU, and will improve almost any team she is on, but she is not broken.
I will first state that when evaluating a suspect, I judge them of their individual merit, whether they themselves are powerful enough to break a tier. I therefore discount any arguments centering around team support, as the Pokemon in question is thus not broken of its own merit. I also discount any argument regarding a Pokemon shifting a metagame. I do not accept this position as a valid argument because every Pokemon shifts a metagame, and when powerful threats are introduced into a tier the metagame will shift irrespective of the power level of the Pokemon.
Now, there are several Pokemon that can effectively and consistently beat Nidoqueen. Specially Defensive Slowking is only 2HKOd after rocks by Thunderbolt, and can switch out for multiple opportunities to switch in again should it be predicted and is therefore a counter (note that the Queen user is forced to Thunderbolt twice for the KO and thus must Tbolt turn 2). Uxie is the most common Nidoqueen counter, and can switch in against Nidoqueen multiple times. Gardevoir is a lesser used counter that fills the same role as Uxie. Cryogonal is an excellent check to Nidoqueen, fearing little from it beyond a predicted Fire Blast. Clefable can likewise check Queen bar the rare Focus Blast. There are similarly several bulky Pokemon such as Druddigon that don't like taking one or two attacks from Nidoqueen but can severely threaten it if they get in safely. Thus it can be said that there are 3 good and viable queen counters, a few strong checks, and a bunch of weaker checks to Nidoqueen. These Pokemon are options for Stall and Balanced teams to use to compete without putting yourself at an immediate disadvantage. Combinations such as Uxie+Wish Clefable can likewise be used to cover Nidoqueen as well as several ther Pokemon while keeping the team healthy.
To address Oglemi's other first questions, while adding Nidoqueen to a team will only benefit it the majority of the time, it is not required to have a successful team in RU. Offensive teams can quite easily function effectively without it, and stall teams will often not consider running it at all. Not running Nidoqueen does not negatively impact you, unless you decide to use a Specially Offensive Hyper offense team without the best Special Attacker in the tier.
Now to address the statements that Nidoqueen destroys stall, these statements are only true insofar as they destroy traditional RU stall, which was based around having a counter for everything. Nidoqueen's list of complete counters is very small because of its versatility which hampers the form of stall. However, Pokemon such as Hypno, Musharna, and Gardevoir are viable counters to Nidoqueen on top of the previously mentioned options to check it. While some may claim that this is overcentralising, it is no different from running Regirock on a stall team to immunize oneself from Moltres.
There is often a claim that Nidoqueen is broken because of its susceptability to passive damage. I believe this simply makes it an inherently better Pokemon, improving its durability, not that it makes Nidoqueen overpowered. Despite the fact that it is immune to Poison, Burn, and Toxic Spikes, while resisting SR, the fact remains that any damage it incurs IS permanent. Any weak attacks it switches in on, and random burns it might incur trying to come in on a Spiritomb are permanent decreases in its health. On top of that, it is very vulnerable to Spikes, an excellent option in the current metagame. The end result is that Nidoqueen cannot switch in with impunity, it must come in on double switches or after KOs a large part of the time. While it is certainly a dangerous Pokemon when in play, it often has difficulty getting into play in the first place.
I've talked for a bit so I'm going to conclude with the fact that Nidoqueen does not impact Offensive teams at all, in large part due to her subpar speed. Almost every Pokemon on an offensive team will be able to OHKO Nidoqueen or at least 2HKO it. This forces Nidoqueen to play safely on the few occasions it manages to get in lest it be KOd. This means that if offense isn't in a position to outright KO Nidoqueen it will often be able to get in another teammate that can through inherent resists, such as Fire Blast on a Kabutops, or through various immunities, such as Earth Power on a Rotom or Aerodactyl. Offensive teams will also frequently carry bulky Pokemon that can switch in on most of Nidoqueens options and force it out or KO it, including Gallade or Druddigon. Furthermore, most offensive pokemon will outspeed Ndioqueen, and offensive teams will frequently be in a position where they can sacrifice a Pokemon to do, say, 70% to Nidoqueen thus removing it as a threat.
In short Nidoqueen is not very good against offense, is excellent against stall, but can be dealth with by the creative (users blarajan and Oglemi have made successful stall teams accounting for Queen) and can significantly threaten balance, with the caveat that it itself is often significantly threatened by balance.
To summarize, I do not believe that Nidoqueen is broken in RU of its own merit. Therefore, Do not Ban Nidoqueen. i will conclude with a quote I found in an old thread about suspect testing that seems to summarize many of my feelings about this, and other suspect tests.
"It seems we've been moving from banning only that which is broken, only what must be banned to have a balanced metagame, to attempting to ban everything we don't like."
