The exact plot is super-needlessly secret right now, although it has been released that this time the film will include one person undergoing laser eye surgery. Just think of the fun! Will the person be so hopelessly stupid that as their friends are dying mysteriously, they decide to go and let lasers near their eyeballs, or will this poor sap be the first victim? And how many more installments until its Final Destination Under Water, Final Destination in the Air, or Final Destination in Space? At some point, they'll have to add a new twist other than 3D jumps.
As for Heisserer, well, he is on a horror role these days. He wrote the final draft of the new A Nightmare on Elm Street, and penned the script for the remake of The Thing, which is currently shooting in Toronto. Should his sequels and remakes do well, we'll probably see a whole lot more of him in the next few years.