Reasons Rey should’ve been the villain: It would’ve preserved Anakin’s redemption
One of the biggest concerns with the sequel trilogy and especially in bringing back Emperor Palpatine was the fact it would lessen the impact of Anakin’s sacrifice. He gave up his life to save Luke from the Emperor and in the process redeemed himself when he tossed ol’ Sheev over the rail to his demise down to the core of the Second Death Star.
Bringing back the Emperor made this a much lesser sacrifice, but what made it worse was having Anakin’s own grandson, Ben Solo also fall to the Dark Side. Apparently Anakin’s fall from a hero to a villain and back again wasn’t enough for his future family to not make the same mistake.
One would think his parents and his Jedi Master Luke, would have told him the story of his grandfather and his fall to evil so that he would be sure to not follow down the same dark path. It was odd that the filmmakers of the sequels and the story brain trust decided to have Ben find this information out from a public broadcast rather than from his family.
With Ben being a Jedi through this trilogy, and not succumbing to the Dark Side, it would’ve made Anakin’s sacrifice more meaningful. While he may not have been able to stop the Emperor from making his way back to the land of the living, he would’ve been able to secure his family’s future and keep them from falling to the Dark Side the way he did.