Peter Chiarelli signed Koskinen's extension and was fired like 48 hours later
Knife. Twist it more. Please. Need it.
If the organization didn't believe in Shero, why let him make the Hall trade?
This isn't months later...we talkin' weeks here.
I have a couple ideas on that:
Shero's been behind the wheel of this organization for the past 4(?) years: there was a substantial mess left behind in the wake of fueling the "playoff" teams between 2006 and 2012. The draft record is abysmal beyond three names over that entire span. Eventually, the Devils needed to pay for not insulating the foundation of the franchise. Over Shero's tenure, the drafting has barely improved - they're getting NHL players out of the 1st Round now at least - but everything else remains abysmal. The NHL team is a dump, and the AHL team is no better.
One of two things have happened here: Shero pooched the Hall trade or management simply wanted to go another way. It's debatable as to why ownership would keep him around in order to make the initial Hall trade, but having a tenured guy that can possibly pull the odd favour around the league tends to make those transactions easier and more lucrative. Alternatively, you get Chiarelli-esque deals out of the same line of thought. Big risk. If we assume that ownership was dissatisfied with the return for Taylor Hall, then firing Shero before he bungles the trade deadline needed to happen, albeit sooner. Doing it now or as early as possible gives the interm and his guys enough runway to start assessing the market in order to prepare trades for (potentially) Palmieri, Simmonds, Subban, and Vatanen.
If management simply came to the conclusion that they wanted a philosophy change - tenure for NHL management is typically in the 5-year range, if your plan isn't working by then, you move onto the next guy - the timing of this is still incredibly bizarre UNLESS there's going to be a top-down reorganization and firing throughout upper management. It's kind of inverse to how the Leafs managed their restructuring: Toronto fired everyone weeks before the draft, but already had the majority of the research and work done ahead of time. In this case, management wants a clean slate with making these decisions. Again, the timing is stranger than all hell; it would make the most sense to maximize the time you give the guys coming in, thus a restructure should have happened the minute after Hall was traded. There might be potential for the legality of firing everyone and contract-related shenanigans that may have pushed this decision into the halfway point of the season, but I don't know enough about the contract structure of any NHL front office to even attempt guessing at that.
TL;DR if Shero didn't pooch the Hall trade, the best time to fire him was after said trade. The second best time was as soon as possible.