Here's How I could see it.
The Game has two sides(Sort of Like RSE)
The Crowned Guy wants to turn Isshu into a more natrualized stated in Black,through which he can rule because of he knowledge of technology and the future and such.N and Player team up to take him down at various parts of the story, similar to Steven or Barry in Pt.To do this, he needs to summon Reshiram.After Crownie's defeat, Reshiram goes on a rampage, making things around Ishhu turn more naturalized.The player has to capture or defeat it to bring it back to peace.
And Then he tries to make it more technological in White,through which he can rule over because he is the creator of the future.TO do this he needs to Summon Zekrom.and all of the things metioned above happened.
This is what could happen if GF gets lazy with Ideas. Only reason I would support this is because of the RSE remake theory.