Now that Crota's End has been out for awhile, I feel that Vault requires more teamwork than Crota's End. You can solo all sections in Crota, yet not in vault.
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I would say VoG has a more organized teamwork with a set number of people to make things work. On Crota you can switch up how many people are assigned to a task and how many are needed to get things done, that's why you don't need 6 to complete it.