Ok so here's a random idea that came to me a few moments ago. If the idea has been talked about before, I apologize in advance.
I was looking through my games and saw Pokemon Conquest. I've said in a number of threads before "hey, Pokemon Conquest 2 would be pretty cool".
As I thought about it more today, I realized maybe it could work. So say Game Freak and Tecmo collaborated again on a sequel. Now I know Tecmo is known for their Ambition of Nobunaga games and whatnot but hear me out. What if Tecmo were to expand beyond just warlords in feudal Japan? What if to go along with the European themes in Pokemon X and Y, Tecmo wanted to incorporate the King Arthur legend? Yes, probably little chance of that happening but I think it could work in theory and yes I know the game is based on France. It might need some leaps and twists in the story to work out into an E rated Pokemon game as well but it could work.
Arthur could start out as a young character like the main character in Pokemon Conquest. It starts off similarly with the legend, he draws the sword, is made king and given a Pokemon as his vessel (let's say Eevee). But not many care that he drew a sword from a rock and he is only able to rule a small fraction of the land. The main goal could be for him to gather the greatest knights of the land to be a part of his court. He could challenge other knights and prove that they should follow him and be a part of his Round Table. Basically a similar setup with the original Pokemon Conquest but maybe with the 3DS, the battlefields will be more varied with more Pokemon and strategy involved.
Throw out the whole Guinevere and Lancelot schtick, that will keep it at an E rating (maybe lol). And rather than have Mordred as Arthur's son, make it his half brother or something who wants to defeat Arthur and rule the land himself. Xerneas can have an Excalibur like role, as a Pokemon that will aide Arthur once he proves himself to be able to lead as a king.
Yveltal, Pokemon of destruction who burns and destroys castles could work into the story. Main enemy Pokemon used by main antagonist maybe?
Rather than have Arthur die in endgame, twist the story a little, it doesn't have to follow 100% faithfully.
Well this is what I came up with. I probably forgot a couple of things and wasn't able to type them up, otherwise...yeah.
:3