Disaster Area wanted me to post this idea which he'd discussed with shrang, but shrang decided not to post.

His suggestion is that if we were to implement this in Gen 6, rather than leaving the generation somewhat ruined, would be to begin to do this, but stagger the approach. So, whilst we play the new OU for a few months, the other tiers would either play their pre-change tier or their BW equivalent, dependent upon what solution is agreed upon, and in due course they change over to the new ORAS tiers as they are developped.