I'd just like to point out that there are enough pokemon in the tiers from Ubers to RU to just do those for 4 years, which is the normal amount of time in a generation. We could just do those, the better pokemon, rather than spending loads of time doing useless POTW's on NU pokemon. If a NU pokemon came up through the RNG, then you could just roll it again. This would mean better pokemon, and it would also mean that OU pokemon don't get POTWs just because they're weren't selected by the RNG.
There are also 5 unreleased pokemon, so that's a total of 213 pokemon from Uber to RU - exactly 4 years and 5 weeks worth of POTWs. Even if the generation did last longer than that, we could just pick the best pokemon from NU, or do some POTWs again, because pokemon do go from Uber to OU, and OU to Uber. Also, metagames shift sometimes as new strategies emerge. Volt-turn is now one of the most used strategies, and it wasn't so popular earlier on in BW. Pokemon such as Shaymin, who suddenly become a whole lot more viable as volt-turn counters, are suddenly a lot better, and therefore they have different roles, and can be updated.
Just a thought. All I'm saying is that we don't need to be doing useless POTWs for completely not viable NU pokemon.