BL and UU are defined in terms of OU usage, but is NU based on how often the Pokemon are used in OU or in UU? I recommend basing it on how often they are used in UU, because there won't be that much difference in OU use between, say, Whiscash and Meganium, but in UU, I'd suspect that Meganium would be used a bit, but Whiscash would still never be used, so if you don't want to see stuff from OU or UU (which is generally what a new tier is for), then NU probably ought to be the elimination of the UU staples. Second, and this one is probably going to be a bit more controversial, I think we ought to consider raising the bar for UU and, therefore, NU. Right now the BL tier is absolutely massive. If we allow stronger Pokemon into UU from the BL tier, then those stronger Pokemon would likely balance each other out, and it would remove more Pokemon from the 'limbo' of BL, so to speak. This would lead to the UU tier being massive, so we could bump a lot of those down to NU. This would possibly lead to some interesting strategies being viable in NU, instead of it being the trash heap of Pokemon that it was in ADV (because really, Choice item or Resttalk as the only strategies, aside from the occasional NP passing Minun isn't really that interesting).