This isn't really help, but I have played the black and white cartridge and wondered if the 3ds DX version is worth it if i already played the original!?
If you loved the game, then it is absolutely worth it. I played it for the first time on the 3DS and it's awesome. Even if you already played the original, it's worth it if you loved it.
Well, I think it has some improvements and the gameplay is a little better, but I think they just wanted to update the game and make it better for the enjoyment of others.