There are two versions of the Next Novel Epilogue. One is a set up for a sequel that will be written (or might already be finished). I don’t mind these because they help you decide if you want to read more about those characters and that world.
The second version is annoying. Having already written a complete novel, the writer has an idea for a sequel but 1) knows it is a snack and not a meal, or 2) doesn’t have the time and energy to devote to it. Instead of stashing away the brief notes for another day, the writer turns them into an epilogue. Having already experienced the crashing storm of the novel’s concluding chapters, the reader is now caught in the drizzle of an unsatisfying outline of the characters’ next adventure.
Coming up: Epilogues That Satisfy