For major decisions it is a good idea to appoint a 'Devil's Advocate' in your team. His (or her) role is to question everything.
The Cambridge Dictionary defines 'Devil's Advocate' as "someone who pretends, in an argument or discussion, to be against an idea or plan that a lot of people support, in order to make people discuss and consider it in more detail"
One of your team members can play that role, but there's always a chance that people are insulted and/or can not differentiate between the role and the person.
Hans can serve as your Devil's Advocate. Because he is free to ask and say anything you'll get an open discussion. Biases, both personal biases and team biases, are mitigated. The result? A better decision making process leading to a better decision and in the end ... better outcomes.