I’m positive anything I put here you guys have already thought of but here goes anyways… I think a little more randomness would do wonders during blood moons. It’s currently way too easy to game the AI because their behavior is so predictable. Having some zombies that don’t just follow the same defined path to the user in an endless loop would really increase the intensity.
Instead of how they will single file jump up block stairs in a really slow animation that gives you plenty of time to shoot them, maybe some just destroy the blocks underneath you? Like less prioritization of getting to your height and more bringing you down to their height.