Speaking about thing that later got retconned, was it ever the rules that you had to fight a champion after the elite 4?
In RBY the game never mentions anything about having to fight someone after the Elite 4, just that you become the champion after that. The battle against your rival was supposed to be a little plot twist and even Lance mentions after defeating him that you would had become the champion if it wasn't for your rival defeating him just minutes before
To me it just seems that the "battle against the champion" was supposed to be just in that specific ocassion, but GF probably thought that it would feel incomplete and lame that the following games wouldn't feature a "final battle" in the same way that RBY did.
So, what are your thoughts about this /vp/?