It completey destroys story credibility. What does it call itself? It's name is VOYAGER, it reads V___GER and just compacts what's left into a name? It clearly understands the English language, knows there is a gap, is smart enough to understand why that part of it's nameplate is obscured in a way that could be easily remedied, yet fudges it's name for the sole purpose of a big reveal at the end of the movie. No other reason, no in-universe justification. Khan was aware of how to fly a starship since "Space Seed", we saw him flying the Reliant solo at the end of the movie. It's in no way plausible that anyone without learning difficulties would mistake space for some Space Invaders-like 2D realm. Add to that the intelligence-insulting "code" used earlier in the movie - "hours will seem like days" If Ceti Alpha VI isn't there anymore, how did the Reliant ever mistake Ceti Alpha V for it? Did they somehow mis-count planets when they entered the system and set a course? It makes no sense. If you want to believe the Genesis Device is plausible science fiction, let alone plausible within the framework of Star Trek's technology, go right ahead. So why does Sarek want Spock's body brought to Vulcan when he meets with Kirk in his appartment, before Spock's torpedo tube is located intact on the Genesis surface? The real-world reason is that the Grissom scene was originally to open the movie, but was moved further back, giving the impression Sarek somehow knew Spock would be reborn there. Yet they just happened to pick up Spock and leave when he was the correct age? Thats a big part of the movie hinging on a big happy coincidence. And how exactly did Genesis turn a corpse into a young child? No, but an example of Trek veering into cartoon land. That's warm, cozy nostalgia talking.