I agree that CC Zack could pass as an extension of what little that we saw in the OG, but would it have killed them to give him a slightly more nuanced characterization? I mean, I guess it’s probably a consequence of the fact that for some reason they decided to go down the route of very literal Heroes and Monsters.
I also disliked the whole “Be my living legacy” thing, though I guess I’m probably in the minority on that front. Given what happens next, it feels like he’s almost giving Cloud permission for kinda stealing his identity, or at least part of it. And one thing I always loved about Cloud’s whole “identity theft” of sorts is that there are so many subtle layers to it, and it’s not so clear-cut, which may also be why so many people are a bit confused about the whole thing: as others have pointed out, he doesn’t just replace and copy Zack, his fake persona is more like a clumsy hybrid that informs us of Cloud’s thoughts about the kind of man he aspired to be.
While Cloud is a completely blameless victim of it all, and while it’s something that is perfectly integrated in the game’s plot and lore thanks to Jenova and Sephiroth’s plan… Zack was exactly what Cloud always thought he wanted to be. Just a small town kid, who told everyone he was going to become a big badass SOLDIER because he was that special and then actually did it, someone who certainly had no problems with girls and that could speak to Sephiroth almost as an equal. I… always felt like Zack’s line removes some layer of ambiguity from this complex, extremely well-written web of subconscious thoughts and desires, but maybe that’s just me.