My take on the goalie situation is that the Wings ultimately not end up sticking with 3 this season.
The major factor in the Wings going with 3 last year (aside from the inconsistencies and early injury) was not wanting to have to dip into GR for a goalie, if needed. They wanted Cossa to get a significant workload in his first full season in the AHL, concentrate on developing, and not worry about getting called up. And Hutchison, while fine in the AHL, is not a viable NHL option. So, the Wings' NHL options for goalie rested solely with what they kept on the NHL roster.
This season, with Campbell in GR available for a call-up, and probably even Cossa too, the Wings should feel much more comfortable only keeping 2 goalies on the NHL roster, because if the need arises, they probably feel better about their GR options for a fill-in when needed.
On top of that, their need for that roster spot to fit a forward or defenseman in is greater than it was last year, as well.