Coaches that come in mid-season never just wholesale change the system. They make tweaks to whatever is already in place, they make personnel changes, but they never just say "okay throw whatever this dogshit nonsense you've been coached out the window, here's how we do things now".
What an impossible point to follow. People don't want to sign overpriced free agents, how does that relate to having a veteran team of actually talented hockey players? The Devils are young, they have a brand new coach who taught them a brand new system, they're missing 2 of their top-4 defenseman, and they're currently playing to a 100-point pace.
This isn't the catastrophe some people are making it out to be lol