What Off-Season Coaching Hire was the Worst?

I thought about the hiring of former Oakland Raiders coaches. But honestly, this one has me puzzled a bit.

The 49ers were riddled with injuries in 2014, but their problems lie beyond that. What are the 49ers' three resolutions for the upcoming season?
After the departure of now Michigan football head coach Jim Harbaugh, San Francisco has many questions to answer, and many holes to fill.
The Jim Harbaugh era in San Francisco has come to an end. Which big names appear to be fits to replace him as head coach?