Sorry, should have clarified - I meant that each member of the flight crew has a loved one in stasis (not part of the flight crew).

To get leverage on them to ensure that they complete the mission as safely as possible?

Since a lot of movies do this stupid trope, it's okay for this movie to do a stupid trope?

Yes, why didn't Crudup just shoot David? Why was he so trusting even after he saw David's horrible creations in his workshop?

Why didn't the ship's onboard computer detect that the android wasn't really Walter? Did David have a high-enough security clearance to override it?

I don't think a comparison between present-day Jon Steward and Trevor Noah is fair. It took about a year of Stewart hosting the Daily Show in order for him to find his voice and to steer the show where he wanted it to go.