New Vault Defense idea

Me and the Immortals been thinking, instead of dropping us in at the beginning and making us run after the Shadows. Why not drop us in at the boss and let us defend the gate? Maybe even have us replace the end boss? It just really seems dumb that we would be inserted after the 3rd floor and have to chase after the enemy. Even when we are triggered during the other floors (if a party doesn’t kill Wardens) we should come out from the end gate and chase them back. That is the new idea that we came up with anyways. What does everyone think about this idea?