...You know, that's it exactly. Everyone needs an editor, and you run into problems when you start thinking you don't (Anne Rice, I'm looking at you).
And it's kinda like, Squeenix knows FF7 is a big ol' cash cow, and the fans will always come, waving their money in the air, as long as "Final Fantasy VII" is stamped on it somewhere. So they don't even really try.
And thus, Gackt is grafted onto FF7.
And there's a reason why I never saw all of the prequels to the Star Wars trilogy--I got as far as the first one with it's "mitachlorians," immaculate conception, and Jar-Jar Binks, and went, "...no." I'm not regretting that decision at all.