Each of these franchises ruined there characters as the series of films went on. The storylines became thinner & thinner and the "supernatural" was usually brought in to explain why these characters wont die or rise from the grave again and again. Also the characters became less scary as the films went on...Freddy became a comedian, Jason went into space, Amityville House demon went from house to lamp, Leatherface became a transvestite, Michael became part of an occult, Pinhead went into cyberspace....... Not the fascinating, frightening characters that terrified us in there first films.
Also each of the above named films has been remade, most ruining there legacy there based on.
For example: Remember Dr. Loomis played by Donald Pleasance in the Halloween franchise, he was such a loveable character in the original franchise, a character you rooted for, felt his guilt & pain over Michael. The you get Rob Zombies Halloween, The new Dr. Loomis became a fame hungry, money powered asshole!
I personally think its time to put these franchises to rest, just leave them be now. No more trying to think up ways to resurrect them, put that work in to new, original ideas and that way we'll resurrect a dying genre.
*As of writing this the following films are being made or released: "Texas Chainsaw Massacre 3D", "Halloween 3D", "Hellraiser: Revelations", "Amityville: The Legacy 3-D" & also "Amityville: The Lost Tapes"