When you assigne the approval step to multiple users or a group of users, it is possible to specify the number of approvers needed. It is possible to chose between Single approver, Majority, percentage or all.

In many cases you only want two set of eyes from the on a document. If you assign a group where the number of members often changes, you cannot really use any of the options available.

Please add the option to enter the number of approvers needed.