Have Michael break out on his own without Sartain’s help. He did it himself in the original, he can do it again in 2018.
Remove Sartain entirely. He’s not needed, and the Loomis role is already being filled by Laurie in 2018.
Take the scene of Laurie visiting Allyson at the school, and have it take place after Michael’s escaped. Have him watch them for several minutes. After Laurie walks off, Michael lingers on Allyson, implying he has a new victim in mind.
Add a scene of Michael stalking Allyson and her friends during the daytime. This will set up Michael knowing about Allyson’s friends later in the movie.
After Allyson discovers Oscar’s body, have Michael chase Allyson to Laurie’s house, thus explaining why he ends up at Laurie’s house for the third act. No need for Sartain acting as Michael’s uber.
I’d remove the scene of Michael going door to door killing random people with zero build up. He’s a creepy stalker who takes his time with his kills. He’s not Jason or some mindless killing machine.
I wouldn’t have Michael trapped in the burning basement at the end. He’s already burned twice, it’s tired and boring at this point. The way it’s done is also too ambiguous. I’d have Michael die a more unique and definitive way.
I would redo all the dialogue from the ground up. It’s rough to say the least.
Laurie would still be traumatized, but her house wouldn’t be booby trapped Home Alone style. She also wouldn’t be portrayed like a doomsday prepper.
She’d still have a few gun though, and would still be riding around town looking for Michael like she does in the movie.
Laurie would start the movie off in a semi functional state, with a drinking problem and strained relationship with her family. But after Michael escapes, her mental health will deteriorate. She’ll become more paranoid the longer she looks for Michael, and realizes he’s after Allyson this time and not her.
I would remove the podcasters visiting Laurie, it’s a terrible scene in general. I’d add an extra scene of Vicky, she’s really likable.