I just watched the scene where Xion died and something she said hit me. Everyone(blanket statement) says Days was pointless if everyone forgot Xion anyways, and she did nothing worthy, a plot device. However, as she died in Roxas's arms, she asked Roxas to stop Xemnas and free Kingdom Hearts, while Roxas can't remember Xion anymore, he and Riku and everyone else still remembered her for a short while. The memories slowly faded, and the memories of her dying words caused Roxas to go back to The World That Never Was before he forgot entirely, Riku stopped him, and reunited him with Sora. If Xion had never asked Roxas to do that, it's possible he would've stayed hidden from everyone for at least a little while longer, prolonging Sora's awakening and giving Xemnas more time to finish Kingdom Hearts. Xion is also the reason Roxas even left the Organization to begin with. And I understand this could've all been explained through a few cutscenes, but they also wanted to make a game detailing the daily life of Organization XIII. They just mixed the two together. Now excuse me while I hide from the flames.