User blog comment:DMSwordsmaster/So I was browsing Derpibooru, and.../@comment-5207917-20140122113233/@comment-4838972-20140122201421

To answer your question, I don't think that would be feasible. The entire tumblr was initially based on Molly, with Gamer Luna being a character introduced later on. It would essentially be like replacing one of the Mane 6 with another pony. While it could be successfully done, it would still be spitting in the face of the entire history and background of the work in question.