Victreebel is underrated, although, blame Skuntank for that. Things like Skuntank are the only things that actually manage to check it with a Swords Dance + Sleep Powder set, with Sucker Punch and Leaf Blade.
[Must stop talking about Victreebel]
Anyway, I think people seem to be forgetting something in this Regirock discussion. Hippopotas is at #52 [I think, too lazy to check]. Regirock is at #50. So, the possible outcomes are:
We get Regirock, We get Hippopotas
We keep Hippopotas, We don't get Regirock
We don't get Regirock, we lose Hippopotas
There's no situation where Regirock will be in NU, and we'll not have the hippo.
In terms of banning? Regirock is certainly the most broken. Regirock can shrug off Fighting-type attacks, albeit, not without a heavy loss of HP, Curse, then Rest to wall anything physical in the teir. Sp.Def of 100 is also not anything to sniff at. By no means Regirock weak specially, it's just weaker.
Give Regirock a week, I say, before we're all calling for it to be banned.
Regice + Regirock would lose to Fighting types. Besides, we already have NU's Skarmbliss. It's called Milking. Both have reliable recovery, they cover each other somewhat well, the special wall threatens crippling, and very few pokemon can actually handle it [To be honest, very few can handle just one of them :/]
As for banning, I think we're all agreed that something has to be done. Seeing as NU is not afflliated with Smogon officially, there's nothing stopping us from have [Intelligent] votes about suspects. I'm quite sure there's enough reasoning to get Miltank, Espeon, Medicham and Magmortar banned, and also probobly Slowking and Skuntank. Of course, when Smogon starts NU, this will all be voided, it'll be 'unofficial' teiring.