Regardless of the game or medium, I always have this thought about zombies in general. They should either be fast or smart, but not both to keep balance. Super fast jump high zombies should be limited by things like not understanding how to open a door (but maybe could bash through one) and less likely to notice you. Likewise, smart zombies that can use tools (weapons?) and open things should be slower and easier to outmaneuver but perhaps spot you a lot quicker. Of course, it's be cool if newly dead zombies start out smart and uncoordinated but then over time become more mindless but better at getting around so that you have a mix of both smart and fast zombies.