Neo, that's a fair question ... one I'm not qualified to answer. Shanahan and Allen certainly knew who was out there, though, and opted for Haslett, so I'm going to go 'benefit of the doubt' here and accept their judgment that he was the best option available. My guess is he was the best option available with experience---there are surely any number of young, up-and-coming defensive minds they might have tapped, so the option to go with Haslett strikes me as a nod toward wanting a known quantity, with coordinator experience, who can establish a baseline here for the new regime.
Utah, appreciate the insight as always. Absolutely there are reasons why stats turn out the way they do ... and no stat stands alone. I remain hopeful that Haslett's stats, which over time as a whole translate roughly as "meh" to me, look a lot less so in consideration of all the factors at play in each of his six seasons. Still hoping to tap into the reasoned, objective mind of someone who knows the game and has had the opportunity to watch Haslett's defenses play over time.