OG FF7 does introduce Sephiroth perfectly... For that game. That's part of why everyone and their mother knows who he is now. This is not that game.

The Jaws effect doesn't work when A. everyone knows you're aiming for the Jaws effect and B. Jaws is the main antagonist of a multipart series with little to no presence in this section of source material. Not defeating Shinra in pt.1 and then suddenly completely switching antagonists with little to no set-up for pt.2 is fundamentally awful narrative design. They're better served by introducing him earlier, making his and Cloud's connection to each other more prevalent throughout the entire narrative rather than it just suddenly being a thing fifty hours in. It made more sense in og7 because it happened 5-6 hours in, not 50.