The thing is, I find Scream's formula quite boring after 7 films of the same ****. We know what will happen in every movie. Oh, there's a new killer... who will it be? Who cares, Sidney will kill them at the end anyway! They always act like it's gonna be different this time, but it never is.
Anyway, here's my thoughts on Stu. The beginning of the movie literally makes no sense. Why would they travel to Woodsboro to burn down the Macher house and kill two random people? It doesn't really make sense to be anyone. Easy to reveal/retcon it was Stu, since... he'd actually be there. When they called the county morgue, there's no record of Stu's body ever showing up. That's never explained as part of the game our killers are playing. Stu saying "surprise, Sidney" and especially "I always had a thing for you" don't make sense when she was the only person there.
Scream is NOT realistic at all, by the way. In the last few films, characters get carved up like butchered animals and still get away. Heck, every single film does that stupid "always comes back for one last scare" where, somehow, the seemingly dead killer jumps out with full energy and sprints at the survivors. It's absurd.
Stu's injuries are more believable. He got stabbed a few times, but nothing that hasn't been survived in this franchise before. Massive head trauma from the TV... yeah? But if we're talking about realism, there's no way that TV could have been pushed over that easily or shatter all over his face. That isn't actually accurate to real life either.
At least if Stu did come back, people would actually care who the killer is. The problem in Scream is that it's so basic now. There's a random killer on the loose we've never seen before, they kill a few people, they die. What is this, an MCU movie? How do you make seven movies that all repeat the same patterns and not realise that you stopped caring who the killer was decades ago? Especially since the killers NEVER get away and Sidney has unbreakable plot armor because of Neve.
I'm not shitting on Scream as a whole, by the way. It's extremely influential and all of the movies are good to great except arguably Scream 3 and Scream 7. Even then, they're entertaining.