Well...right off the top of my head, I'll give you legendary Alabama AD Mal Moore. Moore hired Dennis Franchione, Mike ("It's rollin' baby, it's rollin") Price, Mike Shula and finally Nick Saban for football, and hired Mark Gott-Fired and Anthony Grant for basketball. I suppose one out of six isn't bad. In addition, under Moore, Alabama football was hit with major violations, and in 2009, had 16 athletics programs (including football and basketball) placed on 3 years probation for misuse of free textbooks obtained by student athletes, who IIRC gave/sold them to other students. Yet Mal Moore is a legend at Bama.
How about Jeremy Foley at Florida? Hired three football coaches in Ron Zook, Urban Meyer, and Will Moosechump. They were really good with Meyer, but he ran a renegade program while Foley turned a blind eye. At any rate, he also hire Billy D and Mike White. That's 3 out of 5 for Foley, and he was regarded as one of the top ADs in the country.
That's two off the top of my head that have had at least 2 bad hires, yet are considered to be legendary athletic directors. I'm guessing if you wanted to do the work, you can find a lot of athletic directors who have survived at least two bad hires.