I not long finished reading Taking Shape 2 (hugely recommended) which deals with unmade sequels.
There was one that really stuck out to me, which was a trilogy mapped out by Shem Bitterman. Timeline wise it would have come after the Zombies, and would have gone to some really interesting places.
Essentially the lead would have been Loomis, with Laurie dying early on in the first part. Annie would have survived an attack to have a bigger role in the sequels.
What really stuck with me though was the treatment of Michael. He would have been a true shape, an evil entity from a liminal space, that breaks through on Halloween. Loomis and the Shape would have been inextricably linked, and by the final film in the trilogy Loomis passes over into the liminal to try and find a way to destroy the Shape. What he finds there though, is for me the crown jewel of the idea. In the Liminal, Loomis discovers multiverses, and not only that, but sees that each universe has its own Shape, which would be the entire franchise that had come before.
It’s a ballsy move and I can see why Dimension would have baulked, but the freedom that would have come from it would have been immeasurable. You could literally do anything you want and have it make sense.
Instead we got Jamie in a series of bad wigs.