The blame falls on the overrated and (now) ineffective defensive minded head coach, who can no longer coach defense.
Arizona has been in the bottom 5 in shots against for much of the time since the 10-11 season, Tippett's second season there. Why is Tippett getting 4 or 5 year extension's and $4 million per? That's the second highest salary (until Quenneville's extension kicks in next year) for a head coach in the league. At least from the salaries that I've seen that are made public.
I'm not saying he definitely can't coach in the league anymore, but his time there should be through. What the hell are they doing with him still there? It's clear that a change really is needed.