It's not like I would penalize anyone who has completed the challenge previously under different standards. I would still recognize anyone who previously completed the challenge. This only applies to people who play the challenge after the changes.
This isn't exactly like Nuzlocke where rules are strictly set in stone. A challenge like this is much more flexible. I understand where your coming from though. I need to give this some thought and maybe discuss it with Sydian, and see how she feels.
I will probably go your way on Emerald, you're probably right on that one. But in B/W, N defeats the Champion, and thus would be the Champion himself, so really, you do beat the champion in your first run. You have just as much opportunity to raise your Pokemon further post game, if not more so, in BW2, so I still strongly believe that rematch battle should remain in those games, since it would mean making it easier rather than harder if you play BW2.
I'm up in the air on Platinum. I'm really not sure what I should do on that game. Just know that I only have the best intentions in taking over this challenge, and I do realize that it is an important challenge. No one will be penalized for playing the challenge under different rules previously though, you have my assurance.