This is the fate at High Bridge with the prelude and 3 acts.....
Players stand where the mobs spawn and spam AoE, making the objective to save the villagers far to easy and kind of not enjoyable. Invulnerable needs to be implemented until they reach the steps. Other suggestions to fates similar to this is randomly spawn an elite version of the mobs that's significantly tougher than the average enemy if there are a certain amount of players (I.E content scaling). Something needs to be done to break up the zergs at spawn points.