since you cant prove a coach is good by his record he can probably pull something out of some orifice proving that they are on the same level or that rivera is better and it will be ok because he's the only one who knows anything.
Well, let's go by the amount of wins added or subtracted by a coach. Harbaugh lost 0.69 worth of win probability accrued to his 4th quarter decision making; notice the top of the metric has coaches like John Fox, Mike Smith, Marvin Lewis and Jason Garrett. Notice the bottom of the list has Bill Belichick, Mike McCarthy and Sean Payton. Rivera is 11th best, Harbaugh is 12th worst.
Not that I'm arguing Rivera is some coaching savant. He's still young, but he's shown a more flexibility and schematic acumen than Harbaugh has, and with a decided talent disadvantage.