It's interesting that a lot of the critcisms of this movie are the fault of John Carpenter.
Critics of this movie single out a few main issues;
1. The hospital setting. It doesn't make sense that it's empty and it's a boring location.
2. The movie relied on gory kills instead of suspense.
3. The sibling reveal.
Carpenter produced the movie, wrote the story, composed the score, was involved in post production and even did some directing via reshoots for this movie. He said the original finished product wasn't scary, so he reshot some of the kill scenes with more gore.
So all story elements (hospital setting, sibling reveal) can be blamed on him and Debra Hill. The gore complaints are all on Carpenter.
Yet people do not wonder if maybe Capenter was a 'one hit wonder' (at least in the slasher arena), or if he got 'lucky' with the original. The original in truth is a very minimalist movie. People like it because they like the music, think it's spooky and because it made an impact (thus people feel compelled to respect it).
I think people give him a pass because he admits he didn't have a fucking clue what he was doing, wasn't fully committed and the fact he has talked trash about this movie before (an abomination and horrible movie, in his opinion) and threw the director under the bus by saying he "didn't have a feel for the material". It is interesting he readily speaks so poorly of it when he and many of his friends and collaborators worked on it.
I guess what I'm wondering here is would this movie have been any better had Carpenter directed it in it's entirity? I don't think so. It's his story, has his score, Cundey's photography and a lot of the criticisms were his ideas so would have been present in his version. Some would say he would have directed the actors better or made it more suspensful, that's possible I guess but I don't think that'd be enough to make this movie much better.
Though I do think if it had his name attached as the director that his fanboys would go easier on it out of respect for him and he himself wouldn't so readily trash the movie.