Halloween is deffinitely a series riddled with problems, and I think it's largely due to there never being an intent to continue the story past the first film, despite leaving Michael Myers still alive and about in the end, that was more to say he was pure evil and that it never goes away no matter what you do and not to setup a sequel. After that, 2 did a nice job of giving a little more story but also wrapping up matters. H3 should have been made as a unique film and not even carried the title Halloween in my mind; once you introduce a character over multiple films, you've bascially setup a franchise and to have a story in the middle that has nothing to do with your core character is crazy. H4 was a decent return to Michael's story up until the last 2 minutes when the story arc of his evil being passable onto Jamie and them being connected began. I really think they wrote that in just to have a shocking ending and in that it succeeded, but it started Michael's character on a tangent that ruined him. The whole Thorn concept of 5 and 6 really held them back from their potential, so while overall they're fun to watch, story wise they're a tough sell. H20 was a nice revisit to an H1 style of film and worked pretty good. Resurrection had a decent premise with the unique filming style, but story and casting wise was very weak and not too good an installment.
As much as I love Michael Myers and films with the character, I just don't think he's a character made for sequels. I'm unfamiliar with Jason and Freddy films, but I get an impression that their killings and actions follow a pattern that can be justified over multiple films. If Michael had never been tied to any particular place or character, and was simply this evil force that came out on Halloween and terrorized places, not just Haddonfield, then you could probably come up with many stories for him to be involved with. Having Michael's motives tied to family and his home really limits your options for storylines and at some point you either have to say we're done with this character or you come up with bizarre plotlines like the Curse of Thorn to try and stretch things out.
