I had some difficulties getting on the past few days. >_> I apologize for that. Tomorrow, I might edit and crop the OP if I can get on and also read the rest of the thread to see what more experienced players have to say.
I vouch for Vespiquen to remain UU, as I have used her myself extensively and she is just absolutely demolishing. Vespiquen easily dismantles many walls and sweepers with STAB Attack Order (with crits, most walls that dont resist it are 2HKOs, but remember this has only base 80 attack and no Choice item versus things desgined to take hits), combined with the fact that she can easily shrug off anything but Rock attacks, which can still be survived with a Roost. SE Hidden Powers normally do in the range of 30-40% (Fire and Ice are most common) from big sweepers who do not have access to Thunderbolt, Ice Beam, or Flamethrower, and even Pokemon with access to those have similar 3HKO numbers when Vespiquen can 2HKO back, and obviously less for Tbolt and IB when Roost is used. Note that this is with only 252 HP invested in defenses: I run Brave and 252 Attack for the rest. To put this in perspective, Spiritomb preforms a similar job, to take out some walls and sweepers. While it has a better typing and movepool (the excellent STAB makes up for worse offensive stats), let me point out that it has 50/108/108 defenses, while Vespiquen boasts 70/102/102 defenses. In my honest opinion, 20 more HP makes more of a difference than 6 less defenses, yet nobody complains of Spiritomb's awful defenses (again, I am only comparing base stats, not the factors of typing right now for the purposes of perspective). Yeah, yeah, plenty of things wall it: but that's not the end. Vespiquen can always be counted on to get an enemy KO, even when a status cripples her, because Destiny Bond on such a defensive Pokemon is worse than Explosion because there is no accounting for types, offenses, etc. As exhibited in one of my warstories, I once stuck Vespiquen in the way of an unsuspecting Regirock late game when the means to take it out were limited. I proceeded to win the match, and I have won many matches simply by sticking Vespiquen as a sacrifice to take out the opponent's most menacing Pokemon. You can kind of say it's like a mini-Wobbuffet, especially since I run her on a Trick Room team. While Vespiquen obviously doesn't trap anything, the sheer element of surprise works like a Venus fly trap to potential counters. I will find some logs and give examples. As mentioned before, Roost is also big, since it pretty much removes the majority of Vespiquen's weaknesses and Rock attacks only do regular 2x damage, all for the cost of trading a Ground immunity to justa plain resistance. I usually find it a turn of peace when I heal a lot and have little damage done in return. Pressure-stalling, while very situational due to a weakness to status, will come in handy once in awhile.
Given the current NU list, even the Pokemon that resist AO will be given serious trouble (Aerial Ace is run for Poison and fellow Bug types), especially considering crit+awful defenses of NU's flying types+excellent defense as mentioned before. If Vespiquen is allowed into NU, practically every team will be forced to run Steel type + Rock attack, but that doesn't even matter because of Destiny Bond. Bastiodon and Wormadam-S are the only true counters I can count, by Toxi-stalling to death one on one. Of course, this is all if Vespiquen is used correctly, which given the analysis, is rare.
